![[python学习笔记]Day2](https://image.shishitao.com:8440/aHR0cHM6Ly9ia3FzaW1nLmlrYWZhbi5jb20vdXBsb2FkL2NoYXRncHQtcy5wbmc%2FIQ%3D%3D.png?!?w=700&webp=1 "[python学习笔记]Day2")
摘要：
对象
对于python来说，一切事物都是对象，对象基于类创建：
![[python学习笔记]Day2](https://image.shishitao.com:8440/aHR0cDovL2ltYWdlczIwMTUuY25ibG9ncy5jb20vYmxvZy8xMDA2MDgxLzIwMTYwOC8xMDA2MDgxLTIwMTYwODEzMTIyMDQzMTU2LTE5NzQ3NzcwMzYucG5n.png?w=700&webp=1 "[python学习笔记]Day2")
注：查看对象相关成员 var，type，dir
基本数据类型和序列
int内部功能
class int(object):
def bit_length(self): # real signature unknown; restored from __doc__
#返回该数字最少二进制位数
"""
int.bit_length() -> int
Number of bits necessary to represent self in binary.
>>> bin(37)
'0b100101'
>>> (37).bit_length()
6
"""
return 0
def conjugate(self, *args, **kwargs): # real signature unknown
""" Returns self, the complex conjugate of any int. """
pass
@classmethod # known case
def from_bytes(cls, bytes, byteorder, *args, **kwargs): # real signature unknown; NOTE: unreliably restored from __doc__
"""
int.from_bytes(bytes, byteorder, *, signed=False) -> int
Return the integer represented by the given array of bytes.
The bytes argument must be a bytes-like object (e.g. bytes or bytearray).
The byteorder argument determines the byte order used to represent the
integer. If byteorder is 'big', the most significant byte is at the
beginning of the byte array. If byteorder is 'little', the most
significant byte is at the end of the byte array. To request the native
byte order of the host system, use `sys.byteorder' as the byte order value.
The signed keyword-only argument indicates whether two's complement is
used to represent the integer.
"""
pass
def to_bytes(self, length, byteorder, *args, **kwargs): # real signature unknown; NOTE: unreliably restored from __doc__
"""
int.to_bytes(length, byteorder, *, signed=False) -> bytes
Return an array of bytes representing an integer.
The integer is represented using length bytes. An OverflowError is
raised if the integer is not representable with the given number of
bytes.
The byteorder argument determines the byte order used to represent the
integer. If byteorder is 'big', the most significant byte is at the
beginning of the byte array. If byteorder is 'little', the most
significant byte is at the end of the byte array. To request the native
byte order of the host system, use `sys.byteorder' as the byte order value.
The signed keyword-only argument determines whether two's complement is
used to represent the integer. If signed is False and a negative integer
is given, an OverflowError is raised.
"""
pass
def __abs__(self, *args, **kwargs): # real signature unknown
""" abs(self) """
pass
def __add__(self, *args, **kwargs): # real signature unknown
""" Return self+value. """
pass
def __and__(self, *args, **kwargs): # real signature unknown
""" Return self&value. """
pass
def __bool__(self, *args, **kwargs): # real signature unknown
""" self != 0 """
pass
def __ceil__(self, *args, **kwargs): # real signature unknown
""" Ceiling of an Integral returns itself. """
pass
def __divmod__(self, *args, **kwargs): # real signature unknown
#相除，得到商和余数组成的元组
""" Return divmod(self, value). """
pass
def __eq__(self, *args, **kwargs): # real signature unknown
""" Return self==value. """
pass
def __float__(self, *args, **kwargs): # real signature unknown
""" float(self) """
pass
def __floordiv__(self, *args, **kwargs): # real signature unknown
""" Return self//value. """
pass
def __floor__(self, *args, **kwargs): # real signature unknown
""" Flooring an Integral returns itself. """
pass
def __format__(self, *args, **kwargs): # real signature unknown
pass
def __getattribute__(self, *args, **kwargs): # real signature unknown
""" Return getattr(self, name). """
pass
def __getnewargs__(self, *args, **kwargs): # real signature unknown
pass
def __ge__(self, *args, **kwargs): # real signature unknown
""" Return self>=value. """
pass
def __gt__(self, *args, **kwargs): # real signature unknown
""" Return self>value. """
pass
def __hash__(self, *args, **kwargs): # real signature unknown
""" Return hash(self). """
pass
def __index__(self, *args, **kwargs): # real signature unknown
""" Return self converted to an integer, if self is suitable for use as an index into a list. """
pass
def __init__(self, x, base=10): # known special case of int.__init__
#构造方法
"""
int(x=0) -> integer
int(x, base=10) -> integer
Convert a number or string to an integer, or return 0 if no arguments
are given. If x is a number, return x.__int__(). For floating point
numbers, this truncates towards zero.
If x is not a number or if base is given, then x must be a string,
bytes, or bytearray instance representing an integer literal in the
given base. The literal can be preceded by '+' or '-' and be surrounded
by whitespace. The base defaults to 10. Valid bases are 0 and 2-36.
Base 0 means to interpret the base from the string as an integer literal.
>>> int('0b100', base=0)
4
# (copied from class doc)
"""
pass
def __int__(self, *args, **kwargs): # real signature unknown
""" int(self) """
pass
def __invert__(self, *args, **kwargs): # real signature unknown
""" ~self """
pass
def __le__(self, *args, **kwargs): # real signature unknown
""" Return self<=value. """
pass
def __lshift__(self, *args, **kwargs): # real signature unknown
""" Return self<<value. """
pass
def __lt__(self, *args, **kwargs): # real signature unknown
""" Return self<value. """
pass
def __mod__(self, *args, **kwargs): # real signature unknown
""" Return self%value. """
pass
def __mul__(self, *args, **kwargs): # real signature unknown
""" Return self*value. """
pass
def __neg__(self, *args, **kwargs): # real signature unknown
""" -self """
pass
@staticmethod # known case of __new__
def __new__(*args, **kwargs): # real signature unknown
""" Create and return a new object. See help(type) for accurate signature. """
pass
def __ne__(self, *args, **kwargs): # real signature unknown
""" Return self!=value. """
pass
def __or__(self, *args, **kwargs): # real signature unknown
""" Return self|value. """
pass
def __pos__(self, *args, **kwargs): # real signature unknown
""" +self """
pass
def __pow__(self, *args, **kwargs): # real signature unknown
""" Return pow(self, value, mod). """
pass
def __radd__(self, *args, **kwargs): # real signature unknown
""" Return value+self. """
pass
def __rand__(self, *args, **kwargs): # real signature unknown
""" Return value&self. """
pass
def __rdivmod__(self, *args, **kwargs): # real signature unknown
""" Return divmod(value, self). """
pass
def __repr__(self, *args, **kwargs): # real signature unknown
#转化为解释器可读取的形式
""" Return repr(self). """
pass
def __rfloordiv__(self, *args, **kwargs): # real signature unknown
""" Return value//self. """
pass
def __rlshift__(self, *args, **kwargs): # real signature unknown
""" Return value<<self. """
pass
def __rmod__(self, *args, **kwargs): # real signature unknown
""" Return value%self. """
pass
def __rmul__(self, *args, **kwargs): # real signature unknown
""" Return value*self. """
pass
def __ror__(self, *args, **kwargs): # real signature unknown
""" Return value|self. """
pass
def __round__(self, *args, **kwargs): # real signature unknown
"""
Rounding an Integral returns itself.
Rounding with an ndigits argument also returns an integer.
"""
pass
def __rpow__(self, *args, **kwargs): # real signature unknown
""" Return pow(value, self, mod). """
pass
def __rrshift__(self, *args, **kwargs): # real signature unknown
""" Return value>>self. """
pass
def __rshift__(self, *args, **kwargs): # real signature unknown
""" Return self>>value. """
pass
def __rsub__(self, *args, **kwargs): # real signature unknown
""" Return value-self. """
pass
def __rtruediv__(self, *args, **kwargs): # real signature unknown
""" Return value/self. """
pass
def __rxor__(self, *args, **kwargs): # real signature unknown
""" Return value^self. """
pass
def __sizeof__(self, *args, **kwargs): # real signature unknown
""" Returns size in memory, in bytes """
pass
def __str__(self, *args, **kwargs): # real signature unknown
""" Return str(self). """
pass
def __sub__(self, *args, **kwargs): # real signature unknown
""" Return self-value. """
pass
def __truediv__(self, *args, **kwargs): # real signature unknown
""" Return self/value. """
pass
def __trunc__(self, *args, **kwargs): # real signature unknown
""" Truncating an Integral returns itself. """
pass
def __xor__(self, *args, **kwargs): # real signature unknown
""" Return self^value. """
pass
denominator = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
"""the denominator of a rational number in lowest terms"""
imag = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
"""the imaginary part of a complex number"""
numerator = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
"""the numerator of a rational number in lowest terms"""
real = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
"""the real part of a complex number"""
几个常用的功能：
1.__divmod__():
all_items = 95 pager = 10 result1 = all_items.__divmod__(10) #__divmod__()功能常用于页面分页，如上共95个数据，每页10个数据。 result2 = all_items.__rdivmod__(10) print (result1,result2)
2.__init__(),构造方法：
n = 19 n = int(19) #这个过程python自动触发__init__构造方法
float内部功能
class float(object):
"""
float(x) -> floating point number
Convert a string or number to a floating point number, if possible.
"""
def as_integer_ratio(self): # real signature unknown; restored from __doc__
#获取浮点数化为分数的最简比
"""
float.as_integer_ratio() -> (int, int)
Return a pair of integers, whose ratio is exactly equal to the original
float and with a positive denominator.
Raise OverflowError on infinities and a ValueError on NaNs.
>>> (10.0).as_integer_ratio()
(10, 1)
>>> (0.0).as_integer_ratio()
(0, 1)
>>> (-.25).as_integer_ratio()
(-1, 4)
"""
pass
def conjugate(self, *args, **kwargs): # real signature unknown
""" Return self, the complex conjugate of any float. """
pass
def fromhex(self, string): # real signature unknown; restored from __doc__
"""
float.fromhex(string) -> float
Create a floating-point number from a hexadecimal string.
>>> float.fromhex('0x1.ffffp10')
2047.984375
>>> float.fromhex('-0x1p-1074')
-5e-324
"""
return 0.0
def hex(self): # real signature unknown; restored from __doc__
"""
float.hex() -> string
Return a hexadecimal representation of a floating-point number.
>>> (-0.1).hex()
'-0x1.999999999999ap-4'
>>> 3.14159.hex()
'0x1.921f9f01b866ep+1'
"""
return ""
def is_integer(self, *args, **kwargs): # real signature unknown
""" Return True if the float is an integer. """
pass
def __abs__(self, *args, **kwargs): # real signature unknown
""" abs(self) """
pass
def __add__(self, *args, **kwargs): # real signature unknown
""" Return self+value. """
pass
def __bool__(self, *args, **kwargs): # real signature unknown
""" self != 0 """
pass
def __divmod__(self, *args, **kwargs): # real signature unknown
""" Return divmod(self, value). """
pass
def __eq__(self, *args, **kwargs): # real signature unknown
""" Return self==value. """
pass
def __float__(self, *args, **kwargs): # real signature unknown
""" float(self) """
pass
def __floordiv__(self, *args, **kwargs): # real signature unknown
""" Return self//value. """
pass
def __format__(self, format_spec): # real signature unknown; restored from __doc__
"""
float.__format__(format_spec) -> string
Formats the float according to format_spec.
"""
return ""
def __getattribute__(self, *args, **kwargs): # real signature unknown
""" Return getattr(self, name). """
pass
def __getformat__(self, typestr): # real signature unknown; restored from __doc__
"""
float.__getformat__(typestr) -> string
You probably don't want to use this function. It exists mainly to be
used in Python's test suite.
typestr must be 'double' or 'float'. This function returns whichever of
'unknown', 'IEEE, big-endian' or 'IEEE, little-endian' best describes the
format of floating point numbers used by the C type named by typestr.
"""
return ""
def __getnewargs__(self, *args, **kwargs): # real signature unknown
pass
def __ge__(self, *args, **kwargs): # real signature unknown
""" Return self>=value. """
pass
def __gt__(self, *args, **kwargs): # real signature unknown
""" Return self>value. """
pass
def __hash__(self, *args, **kwargs): # real signature unknown
""" Return hash(self). """
pass
def __init__(self, x): # real signature unknown; restored from __doc__
pass
def __int__(self, *args, **kwargs): # real signature unknown
""" int(self) """
pass
def __le__(self, *args, **kwargs): # real signature unknown
""" Return self<=value. """
pass
def __lt__(self, *args, **kwargs): # real signature unknown
""" Return self<value. """
pass
def __mod__(self, *args, **kwargs): # real signature unknown
""" Return self%value. """
pass
def __mul__(self, *args, **kwargs): # real signature unknown
""" Return self*value. """
pass
def __neg__(self, *args, **kwargs): # real signature unknown
""" -self """
pass
@staticmethod # known case of __new__
def __new__(*args, **kwargs): # real signature unknown
""" Create and return a new object. See help(type) for accurate signature. """
pass
def __ne__(self, *args, **kwargs): # real signature unknown
""" Return self!=value. """
pass
def __pos__(self, *args, **kwargs): # real signature unknown
""" +self """
pass
def __pow__(self, *args, **kwargs): # real signature unknown
""" Return pow(self, value, mod). """
pass
def __radd__(self, *args, **kwargs): # real signature unknown
""" Return value+self. """
pass
def __rdivmod__(self, *args, **kwargs): # real signature unknown
""" Return divmod(value, self). """
pass
def __repr__(self, *args, **kwargs): # real signature unknown
""" Return repr(self). """
pass
def __rfloordiv__(self, *args, **kwargs): # real signature unknown
""" Return value//self. """
pass
def __rmod__(self, *args, **kwargs): # real signature unknown
""" Return value%self. """
pass
def __rmul__(self, *args, **kwargs): # real signature unknown
""" Return value*self. """
pass
def __round__(self, *args, **kwargs): # real signature unknown
"""
Return the Integral closest to x, rounding half toward even.
When an argument is passed, work like built-in round(x, ndigits).
"""
pass
def __rpow__(self, *args, **kwargs): # real signature unknown
""" Return pow(value, self, mod). """
pass
def __rsub__(self, *args, **kwargs): # real signature unknown
""" Return value-self. """
pass
def __rtruediv__(self, *args, **kwargs): # real signature unknown
""" Return value/self. """
pass
def __setformat__(self, typestr, fmt): # real signature unknown; restored from __doc__
"""
float.__setformat__(typestr, fmt) -> None
You probably don't want to use this function. It exists mainly to be
used in Python's test suite.
typestr must be 'double' or 'float'. fmt must be one of 'unknown',
'IEEE, big-endian' or 'IEEE, little-endian', and in addition can only be
one of the latter two if it appears to match the underlying C reality.
Override the automatic determination of C-level floating point type.
This affects how floats are converted to and from binary strings.
"""
pass
def __str__(self, *args, **kwargs): # real signature unknown
""" Return str(self). """
pass
def __sub__(self, *args, **kwargs): # real signature unknown
""" Return self-value. """
pass
def __truediv__(self, *args, **kwargs): # real signature unknown
""" Return self/value. """
pass
def __trunc__(self, *args, **kwargs): # real signature unknown
""" Return the Integral closest to x between 0 and x. """
pass
imag = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
"""the imaginary part of a complex number"""
real = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
"""the real part of a complex number"""
class FloatingPointError(ArithmeticError):
""" Floating point operation failed. """
def __init__(self, *args, **kwargs): # real signature unknown
pass
@staticmethod # known case of __new__
def __new__(*args, **kwargs): # real signature unknown
""" Create and return a new object. See help(type) for accurate signature. """
pass
str内部功能
class str(object):
"""
str(object='') -> str
str(bytes_or_buffer[, encoding[, errors]]) -> str
Create a new string object from the given object. If encoding or
errors is specified, then the object must expose a data buffer
that will be decoded using the given encoding and error handler.
Otherwise, returns the result of object.__str__() (if defined)
or repr(object).
encoding defaults to sys.getdefaultencoding().
errors defaults to 'strict'.
"""
def capitalize(self): # real signature unknown; restored from __doc__
#首字母大写化
"""
S.capitalize() -> str
Return a capitalized version of S, i.e. make the first character
have upper case and the rest lower case.
"""
return ""
def casefold(self): # real signature unknown; restored from __doc__
#小写化，适用于所有国家语言，如英语，德语
"""
S.casefold() -> str
Return a version of S suitable for caseless comparisons.
"""
return ""
def center(self, width, fillchar=None): # real signature unknown; restored from __doc__
#居中
"""
S.center(width[, fillchar]) -> str
Return S centered in a string of length width. Padding is
done using the specified fill character (default is a space)
"""
return ""
def count(self, sub, start=None, end=None): # real signature unknown; restored from __doc__
#统计字符串内子串出现次数，可指定范围
"""
S.count(sub[, start[, end]]) -> int
Return the number of non-overlapping occurrences of substring sub in
string S[start:end]. Optional arguments start and end are
interpreted as in slice notation.
"""
return 0
def encode(self, encoding='utf-8', errors='strict'): # real signature unknown; restored from __doc__
#编码
"""
S.encode(encoding='utf-8', errors='strict') -> bytes
Encode S using the codec registered for encoding. Default encoding
is 'utf-8'. errors may be given to set a different error
handling scheme. Default is 'strict' meaning that encoding errors raise
a UnicodeEncodeError. Other possible values are 'ignore', 'replace' and
'xmlcharrefreplace' as well as any other name registered with
codecs.register_error that can handle UnicodeEncodeErrors.
"""
return b""
def endswith(self, suffix, start=None, end=None): # real signature unknown; restored from __doc__
#判断指定范围字符串是否以某个字符串或子串结尾
"""
S.endswith(suffix[, start[, end]]) -> bool
Return True if S ends with the specified suffix, False otherwise.
With optional start, test S beginning at that position.
With optional end, stop comparing S at that position.
suffix can also be a tuple of strings to try.
"""
return False
def expandtabs(self, tabsize=8): # real signature unknown; restored from __doc__
#把tab转换成空格，默认一个tab8个空格
"""
S.expandtabs(tabsize=8) -> str
Return a copy of S where all tab characters are expanded using spaces.
If tabsize is not given, a tab size of 8 characters is assumed.
"""
return ""
def find(self, sub, start=None, end=None): # real signature unknown; restored from __doc__
#find()定位子串在字符串中第一次出现的位置，无则返回-1
"""
S.find(sub[, start[, end]]) -> int
Return the lowest index in S where substring sub is found,
such that sub is contained within S[start:end]. Optional
arguments start and end are interpreted as in slice notation.
Return -1 on failure.
"""
return 0
def format(self, *args, **kwargs): # known special case of str.format
#字符串格式化
"""
S.format(*args, **kwargs) -> str
Return a formatted version of S, using substitutions from args and kwargs.
The substitutions are identified by braces ('{' and '}').
"""
pass
def format_map(self, mapping): # real signature unknown; restored from __doc__
"""
S.format_map(mapping) -> str
Return a formatted version of S, using substitutions from mapping.
The substitutions are identified by braces ('{' and '}').
"""
return ""
def index(self, sub, start=None, end=None): # real signature unknown; restored from __doc__
#index()定位子串在字符串中第一次出现的位置，无则报错
"""
S.index(sub[, start[, end]]) -> int
Like S.find() but raise ValueError when the substring is not found.
"""
return 0
def isalnum(self): # real signature unknown; restored from __doc__
#是否是字母和数字
"""
S.isalnum() -> bool
Return True if all characters in S are alphanumeric
and there is at least one character in S, False otherwise.
"""
return False
def isalpha(self): # real signature unknown; restored from __doc__
#是否是字母
"""
S.isalpha() -> bool
Return True if all characters in S are alphabetic
and there is at least one character in S, False otherwise.
"""
return False
def isdecimal(self): # real signature unknown; restored from __doc__
"""
S.isdecimal() -> bool
Return True if there are only decimal characters in S,
False otherwise.
"""
return False
def isdigit(self): # real signature unknown; restored from __doc__
#是否是数字
"""
S.isdigit() -> bool
Return True if all characters in S are digits
and there is at least one character in S, False otherwise.
"""
return False
def isidentifier(self): # real signature unknown; restored from __doc__
"""
S.isidentifier() -> bool
Return True if S is a valid identifier according
to the language definition.
Use keyword.iskeyword() to test for reserved identifiers
such as "def" and "class".
"""
return False
def islower(self): # real signature unknown; restored from __doc__
#是否是小写
"""
S.islower() -> bool
Return True if all cased characters in S are lowercase and there is
at least one cased character in S, False otherwise.
"""
return False
def isnumeric(self): # real signature unknown; restored from __doc__
"""
S.isnumeric() -> bool
Return True if there are only numeric characters in S,
False otherwise.
"""
return False
def isprintable(self): # real signature unknown; restored from __doc__
"""
S.isprintable() -> bool
Return True if all characters in S are considered
printable in repr() or S is empty, False otherwise.
"""
return False
def isspace(self): # real signature unknown; restored from __doc__
"""
S.isspace() -> bool
Return True if all characters in S are whitespace
and there is at least one character in S, False otherwise.
"""
return False
def istitle(self): # real signature unknown; restored from __doc__
"""
S.istitle() -> bool
Return True if S is a titlecased string and there is at least one
character in S, i.e. upper- and titlecase characters may only
follow uncased characters and lowercase characters only cased ones.
Return False otherwise.
"""
return False
def isupper(self): # real signature unknown; restored from __doc__
"""
S.isupper() -> bool
Return True if all cased characters in S are uppercase and there is
at least one cased character in S, False otherwise.
"""
return False
def join(self, iterable): # real signature unknown; restored from __doc__
#拼接字符串，将字符串连接起来
"""
S.join(iterable) -> str
Return a string which is the concatenation of the strings in the
iterable. The separator between elements is S.
"""
return ""
def ljust(self, width, fillchar=None): # real signature unknown; restored from __doc__
#居左，类似于center()，rjust()
"""
S.ljust(width[, fillchar]) -> str
Return S left-justified in a Unicode string of length width. Padding is
done using the specified fill character (default is a space).
"""
return ""
def lower(self): # real signature unknown; restored from __doc__
#小写化，只支持ASCII码的‘A-Z’
"""
S.lower() -> str
Return a copy of the string S converted to lowercase.
"""
return ""
def lstrip(self, chars=None): # real signature unknown; restored from __doc__
"""
S.lstrip([chars]) -> str
Return a copy of the string S with leading whitespace removed.
If chars is given and not None, remove characters in chars instead.
"""
return ""
def maketrans(self, *args, **kwargs): # real signature unknown
#做一个对应表，如'aeiou'分别对应'12345'
"""
Return a translation table usable for str.translate().
If there is only one argument, it must be a dictionary mapping Unicode
ordinals (integers) or characters to Unicode ordinals, strings or None.
Character keys will be then converted to ordinals.
If there are two arguments, they must be strings of equal length, and
in the resulting dictionary, each character in x will be mapped to the
character at the same position in y. If there is a third argument, it
must be a string, whose characters will be mapped to None in the result.
"""
pass
def partition(self, sep): # real signature unknown; restored from __doc__
#分割，前中后三部分
"""
S.partition(sep) -> (head, sep, tail)
Search for the separator sep in S, and return the part before it,
the separator itself, and the part after it. If the separator is not
found, return S and two empty strings.
"""
pass
def replace(self, old, new, count=None): # real signature unknown; restored from __doc__
#替换
"""
S.replace(old, new[, count]) -> str
Return a copy of S with all occurrences of substring
old replaced by new. If the optional argument count is
given, only the first count occurrences are replaced.
"""
return ""
def rfind(self, sub, start=None, end=None): # real signature unknown; restored from __doc__
"""
S.rfind(sub[, start[, end]]) -> int
Return the highest index in S where substring sub is found,
such that sub is contained within S[start:end]. Optional
arguments start and end are interpreted as in slice notation.
Return -1 on failure.
"""
return 0
def rindex(self, sub, start=None, end=None): # real signature unknown; restored from __doc__
"""
S.rindex(sub[, start[, end]]) -> int
Like S.rfind() but raise ValueError when the substring is not found.
"""
return 0
def rjust(self, width, fillchar=None): # real signature unknown; restored from __doc__
"""
S.rjust(width[, fillchar]) -> str
Return S right-justified in a string of length width. Padding is
done using the specified fill character (default is a space).
"""
return ""
def rpartition(self, sep): # real signature unknown; restored from __doc__
"""
S.rpartition(sep) -> (head, sep, tail)
Search for the separator sep in S, starting at the end of S, and return
the part before it, the separator itself, and the part after it. If the
separator is not found, return two empty strings and S.
"""
pass
def rsplit(self, sep=None, maxsplit=-1): # real signature unknown; restored from __doc__
"""
S.rsplit(sep=None, maxsplit=-1) -> list of strings
Return a list of the words in S, using sep as the
delimiter string, starting at the end of the string and
working to the front. If maxsplit is given, at most maxsplit
splits are done. If sep is not specified, any whitespace string
is a separator.
"""
return []
def rstrip(self, chars=None): # real signature unknown; restored from __doc__
"""
S.rstrip([chars]) -> str
Return a copy of the string S with trailing whitespace removed.
If chars is given and not None, remove characters in chars instead.
"""
return ""
def split(self, sep=None, maxsplit=-1): # real signature unknown; restored from __doc__
#分割，默认以空格为分割符
"""
S.split(sep=None, maxsplit=-1) -> list of strings
Return a list of the words in S, using sep as the
delimiter string. If maxsplit is given, at most maxsplit
splits are done. If sep is not specified or is None, any
whitespace string is a separator and empty strings are
removed from the result.
"""
return []
def splitlines(self, keepends=None): # real signature unknown; restored from __doc__
"""
S.splitlines([keepends]) -> list of strings
Return a list of the lines in S, breaking at line boundaries.
Line breaks are not included in the resulting list unless keepends
is given and true.
"""
return []
def startswith(self, prefix, start=None, end=None): # real signature unknown; restored from __doc__
#是否以某字符开始
"""
S.startswith(prefix[, start[, end]]) -> bool
Return True if S starts with the specified prefix, False otherwise.
With optional start, test S beginning at that position.
With optional end, stop comparing S at that position.
prefix can also be a tuple of strings to try.
"""
return False
def strip(self, chars=None): # real signature unknown; restored from __doc__
#可以去掉字符串两边的字符，默认为空格
"""
S.strip([chars]) -> str
Return a copy of the string S with leading and trailing
whitespace removed.
If chars is given and not None, remove characters in chars instead.
"""
return ""
def swapcase(self): # real signature unknown; restored from __doc__
#大写变小写，小写变大写
"""
S.swapcase() -> str
Return a copy of S with uppercase characters converted to lowercase
and vice versa.
"""
return ""
def title(self): # real signature unknown; restored from __doc__
#以title格式打印字符串，即首字母大写，其余小写的格式
"""
S.title() -> str
Return a titlecased version of S, i.e. words start with title case
characters, all remaining cased characters have lower case.
"""
return ""
def translate(self, table): # real signature unknown; restored from __doc__
"""
S.translate(table) -> str
Return a copy of the string S in which each character has been mapped
through the given translation table. The table must implement
lookup/indexing via __getitem__, for instance a dictionary or list,
mapping Unicode ordinals to Unicode ordinals, strings, or None. If
this operation raises LookupError, the character is left untouched.
Characters mapped to None are deleted.
"""
return ""
def upper(self): # real signature unknown; restored from __doc__
"""
S.upper() -> str
Return a copy of S converted to uppercase.
"""
return ""
def zfill(self, width): # real signature unknown; restored from __doc__
"""
S.zfill(width) -> str
Pad a numeric string S with zeros on the left, to fill a field
of the specified width. The string S is never truncated.
"""
return ""
def __add__(self, *args, **kwargs): # real signature unknown
""" Return self+value. """
pass
def __contains__(self, *args, **kwargs): # real signature unknown
""" Return key in self. """
pass
def __eq__(self, *args, **kwargs): # real signature unknown
""" Return self==value. """
pass
def __format__(self, format_spec): # real signature unknown; restored from __doc__
"""
S.__format__(format_spec) -> str
Return a formatted version of S as described by format_spec.
"""
return ""
def __getattribute__(self, *args, **kwargs): # real signature unknown
""" Return getattr(self, name). """
pass
def __getitem__(self, *args, **kwargs): # real signature unknown
""" Return self[key]. """
pass
def __getnewargs__(self, *args, **kwargs): # real signature unknown
pass
def __ge__(self, *args, **kwargs): # real signature unknown
""" Return self>=value. """
pass
def __gt__(self, *args, **kwargs): # real signature unknown
""" Return self>value. """
pass
def __hash__(self, *args, **kwargs): # real signature unknown
""" Return hash(self). """
pass
def __init__(self, value='', encoding=None, errors='strict'): # known special case of str.__init__
"""
str(object='') -> str
str(bytes_or_buffer[, encoding[, errors]]) -> str
Create a new string object from the given object. If encoding or
errors is specified, then the object must expose a data buffer
that will be decoded using the given encoding and error handler.
Otherwise, returns the result of object.__str__() (if defined)
or repr(object).
encoding defaults to sys.getdefaultencoding().
errors defaults to 'strict'.
# (copied from class doc)
"""
pass
def __iter__(self, *args, **kwargs): # real signature unknown
""" Implement iter(self). """
pass
def __len__(self, *args, **kwargs): # real signature unknown
""" Return len(self). """
pass
def __le__(self, *args, **kwargs): # real signature unknown
""" Return self<=value. """
pass
def __lt__(self, *args, **kwargs): # real signature unknown
""" Return self<value. """
pass
def __mod__(self, *args, **kwargs): # real signature unknown
""" Return self%value. """
pass
def __mul__(self, *args, **kwargs): # real signature unknown
""" Return self*value.n """
pass
@staticmethod # known case of __new__
def __new__(*args, **kwargs): # real signature unknown
""" Create and return a new object. See help(type) for accurate signature. """
pass
def __ne__(self, *args, **kwargs): # real signature unknown
""" Return self!=value. """
pass
def __repr__(self, *args, **kwargs): # real signature unknown
""" Return repr(self). """
pass
def __rmod__(self, *args, **kwargs): # real signature unknown
""" Return value%self. """
pass
def __rmul__(self, *args, **kwargs): # real signature unknown
""" Return self*value. """
pass
def __sizeof__(self): # real signature unknown; restored from __doc__
""" S.__sizeof__() -> size of S in memory, in bytes """
pass
def __str__(self, *args, **kwargs): # real signature unknown
""" Return str(self). """
pass
常用的功能代码示例：
# _format__()功能在python3中不能使用
# capitalize()首字母大写化
name = 'chenghaoqi is a boy!'
result = name.capitalize() #字符串不可修改
# casefold()小写化
name = 'Teacher iS very tirEd'
result = name.casefold()
# center()居中
name = 'XS'
result = name.center(21,'*')
# count()统计字符串内子串出现次数，可指定范围
name = 'Teacher iS very tirEd'
result = name.count('r',7,18)
# endswith()判断指定范围字符串是否以某个字符串或子串结尾
name = 'Teacher iS very tirEd'
result = name.endswith('d')
# expandtabs()把tab转换成空格，默认一个tab8个空格
name = 'Teacher\tvery'
result = name.expandtabs()
# find()定位子串在字符串中第一次出现的位置，无则返回-1
# 同index()类似，但index()中无结果则报错，而非返回-1
name = 'Teacher iS very tirEd'
result = name.find('r',7,20)
# index()定位子串在字符串中第一次出现的位置，无则报错
# format()字符串格式化
name = 'Teacher iS {0} {1}'
result = name.format('very','tired')
name = 'Teacher iS {name} {status}'
result = name.format(name='very',status='tired')
# join()拼接字符串，将字符串连接起来
name = ['a','e','i','o','u']
result = ''.join(name)
# ljust()居左，类似于center()，rjust()
name = 'XS'
result = name.ljust(21,'*'
# partition()分割，前中后三部分
name = 'Teacher iS very tirEd'
result = name.partition('very')
# replace()替换
name = 'Teacher iS very tirEd'
result = name.replace('very','no')
#split()分割，默认以空格为分割符
name = 'Teacher iS very tirEd'
result = name.split()
result = name.split('r',2)
#strip() 可以去掉字符串两边的字符，默认为空格
name = ' Teacher iS very tirEd '
result = name.split()
name = 'Teacher iS very tirEd'
name.strip('T')
# swapcase()大写变小写，小写变大写
name = 'Teacher iS very tirEd'
result = name.swapcase()
list内部功能
如：
lst = list([123,456,789,'kkk']) >>> [123, 456, 789, 'kkk']
具体为：
class list(object):
"""
list() -> new empty list
list(iterable) -> new list initialized from iterable's items
"""
def append(self, p_object): # real signature unknown; restored from __doc__
""" L.append(object) -> None -- append object to end """
pass
def clear(self): # real signature unknown; restored from __doc__
""" L.clear() -> None -- remove all items from L """
pass
def copy(self): # real signature unknown; restored from __doc__
#浅拷贝
""" L.copy() -> list -- a shallow copy of L """
return []
def count(self, value): # real signature unknown; restored from __doc__
""" L.count(value) -> integer -- return number of occurrences of value """
return 0
def extend(self, iterable): # real signature unknown; restored from __doc__
""" L.extend(iterable) -> None -- extend list by appending elements from the iterable """
pass
def index(self, value, start=None, stop=None): # real signature unknown; restored from __doc__
"""
L.index(value, [start, [stop]]) -> integer -- return first index of value.
Raises ValueError if the value is not present.
"""
return 0
def insert(self, index, p_object): # real signature unknown; restored from __doc__
""" L.insert(index, object) -- insert object before index """
pass
def pop(self, index=None): # real signature unknown; restored from __doc__
"""
L.pop([index]) -> item -- remove and return item at index (default last).
Raises IndexError if list is empty or index is out of range.
"""
pass
def remove(self, value): # real signature unknown; restored from __doc__
"""
L.remove(value) -> None -- remove first occurrence of value.
Raises ValueError if the value is not present.
"""
pass
def reverse(self): # real signature unknown; restored from __doc__
""" L.reverse() -- reverse *IN PLACE* """
pass
def sort(self, key=None, reverse=False): # real signature unknown; restored from __doc__
""" L.sort(key=None, reverse=False) -> None -- stable sort *IN PLACE* """
pass
def __add__(self, *args, **kwargs): # real signature unknown
""" Return self+value. """
pass
def __contains__(self, *args, **kwargs): # real signature unknown
""" Return key in self. """
pass
def __delitem__(self, *args, **kwargs): # real signature unknown
""" Delete self[key]. """
pass
def __eq__(self, *args, **kwargs): # real signature unknown
""" Return self==value. """
pass
def __getattribute__(self, *args, **kwargs): # real signature unknown
""" Return getattr(self, name). """
pass
def __getitem__(self, y): # real signature unknown; restored from __doc__
""" x.__getitem__(y) <==> x[y] """
pass
def __ge__(self, *args, **kwargs): # real signature unknown
""" Return self>=value. """
pass
def __gt__(self, *args, **kwargs): # real signature unknown
""" Return self>value. """
pass
def __iadd__(self, *args, **kwargs): # real signature unknown
""" Implement self+=value. """
pass
def __imul__(self, *args, **kwargs): # real signature unknown
""" Implement self*=value. """
pass
def __init__(self, seq=()): # known special case of list.__init__
"""
list() -> new empty list
list(iterable) -> new list initialized from iterable's items
# (copied from class doc)
"""
pass
def __iter__(self, *args, **kwargs): # real signature unknown
""" Implement iter(self). """
pass
def __len__(self, *args, **kwargs): # real signature unknown
""" Return len(self). """
pass
def __le__(self, *args, **kwargs): # real signature unknown
""" Return self<=value. """
pass
def __lt__(self, *args, **kwargs): # real signature unknown
""" Return self<value. """
pass
def __mul__(self, *args, **kwargs): # real signature unknown
""" Return self*value.n """
pass
@staticmethod # known case of __new__
def __new__(*args, **kwargs): # real signature unknown
""" Create and return a new object. See help(type) for accurate signature. """
pass
def __ne__(self, *args, **kwargs): # real signature unknown
""" Return self!=value. """
pass
def __repr__(self, *args, **kwargs): # real signature unknown
""" Return repr(self). """
pass
def __reversed__(self): # real signature unknown; restored from __doc__
""" L.__reversed__() -- return a reverse iterator over the list """
pass
def __rmul__(self, *args, **kwargs): # real signature unknown
""" Return self*value. """
pass
def __setitem__(self, *args, **kwargs): # real signature unknown
""" Set self[key] to value. """
pass
def __sizeof__(self): # real signature unknown; restored from __doc__
""" L.__sizeof__() -- size of L in memory, in bytes """
pass
__hash__ = None
常用的功能代码示例：
lst = list([123,456,789])
lst.append('jack')
>>> [123, 456, 789, 'jack']
lst.extend([0,'tom'])
>>> [123, 456, 789, 'jack', 0, 'tom']
lst.insert(2,'gg')
>>> [123, 456, 'gg', 789, 'jack', 0, 'tom']
lst.count('gg')
>>> 1
lst.pop()
>>> 'tom'
lst
>>> [123, 456, 'gg', 789, 'jack', 0]
lst.pop(1)
>>> 456
lst
>>> [123, 'gg', 789, 'jack', 0]
lst.remove('gg')
lst.remove('jack')
>>> [123, 789, 0]
lst.sort()
>>> [0, 123, 789]
lst.sort(reverse = True)
>>> [789, 123, 0]
lst.reverse()
>>> [0, 123, 789]
tuple内部功能
如：
tup = tuple((222,333,444,'ggg')) >>> (222, 333, 444, 'ggg')
元组tuple与列表list的最大的区别在于，元组不可修改，而列表是可以修改的。所以元组的内部功能较少。
class tuple(object):
"""
tuple() -> empty tuple
tuple(iterable) -> tuple initialized from iterable's items
If the argument is a tuple, the return value is the same object.
"""
def count(self, value): # real signature unknown; restored from __doc__
""" T.count(value) -> integer -- return number of occurrences of value """
return 0
def index(self, value, start=None, stop=None): # real signature unknown; restored from __doc__
"""
T.index(value, [start, [stop]]) -> integer -- return first index of value.
Raises ValueError if the value is not present.
"""
return 0
注：
![[python学习笔记]Day2](https://image.shishitao.com:8440/aHR0cDovL2ltYWdlczIwMTUuY25ibG9ncy5jb20vYmxvZy8xMDA2MDgxLzIwMTYwOC8xMDA2MDgxLTIwMTYwODEzMTkwMjMxNDIxLTgyMzI1OTk0Ny5wbmc%3D.png?w=700&webp=1 "[python学习笔记]Day2")
dict内部功能
字典是一种无序的序列。
特点：
- 字典的值可以是任意数据类型，包括字符串、整数、对象，甚至字典；
- 不允许同一个键重复出现，如果同一个键被赋值两次，后一个值会覆盖前面的值；
- 键必须不可变，只能由数、字符串或元组充当，不能用列表。
如：
dct = dict({'k1':'jack','k2':12,'k3':'male'})
>>> {'k2': 12, 'k1': 'jack', 'k3': 'male'}
具体如下：
class dict(object):
"""
dict() -> new empty dictionary
dict(mapping) -> new dictionary initialized from a mapping object's
(key, value) pairs
dict(iterable) -> new dictionary initialized as if via:
d = {}
for k, v in iterable:
d[k] = v
dict(**kwargs) -> new dictionary initialized with the name=value pairs
in the keyword argument list. For example: dict(one=1, two=2)
"""
def clear(self): # real signature unknown; restored from __doc__
""" D.clear() -> None. Remove all items from D. """
pass
def copy(self): # real signature unknown; restored from __doc__
#浅拷贝
""" D.copy() -> a shallow copy of D """
pass
@staticmethod # known case
def fromkeys(*args, **kwargs): # real signature unknown
""" Returns a new dict with keys from iterable and values equal to value. """
pass
def get(self, k, d=None): # real signature unknown; restored from __doc__
#根据key获取value
""" D.get(k[,d]) -> D[k] if k in D, else d. d defaults to None. """
pass
def items(self): # real signature unknown; restored from __doc__
#返回一个有(key,value)组成的元组
""" D.items() -> a set-like object providing a view on D's items """
pass
def keys(self): # real signature unknown; restored from __doc__
#返回一个包含所有key的列表
""" D.keys() -> a set-like object providing a view on D's keys """
pass
def pop(self, k, d=None): # real signature unknown; restored from __doc__
#弹出一个关键字key，并返回它的值value
"""
D.pop(k[,d]) -> v, remove specified key and return the corresponding value.
If key is not found, d is returned if given, otherwise KeyError is raised
"""
pass
def popitem(self): # real signature unknown; restored from __doc__
"""
D.popitem() -> (k, v), remove and return some (key, value) pair as a
2-tuple; but raise KeyError if D is empty.
"""
pass
def setdefault(self, k, d=None): # real signature unknown; restored from __doc__
""" D.setdefault(k[,d]) -> D.get(k,d), also set D[k]=d if k not in D """
pass
def update(self, E=None, **F): # known special case of dict.update
"""
D.update([E, ]**F) -> None. Update D from dict/iterable E and F.
If E is present and has a .keys() method, then does: for k in E: D[k] = E[k]
If E is present and lacks a .keys() method, then does: for k, v in E: D[k] = v
In either case, this is followed by: for k in F: D[k] = F[k]
"""
pass
def values(self): # real signature unknown; restored from __doc__
#返回一个包含所有value的列表
""" D.values() -> an object providing a view on D's values """
pass
def __contains__(self, *args, **kwargs): # real signature unknown
""" True if D has a key k, else False. """
pass
def __delitem__(self, *args, **kwargs): # real signature unknown
""" Delete self[key]. """
pass
def __eq__(self, *args, **kwargs): # real signature unknown
""" Return self==value. """
pass
def __getattribute__(self, *args, **kwargs): # real signature unknown
""" Return getattr(self, name). """
pass
def __getitem__(self, y): # real signature unknown; restored from __doc__
""" x.__getitem__(y) <==> x[y] """
pass
def __ge__(self, *args, **kwargs): # real signature unknown
""" Return self>=value. """
pass
def __gt__(self, *args, **kwargs): # real signature unknown
""" Return self>value. """
pass
def __init__(self, seq=None, **kwargs): # known special case of dict.__init__
"""
dict() -> new empty dictionary
dict(mapping) -> new dictionary initialized from a mapping object's
(key, value) pairs
dict(iterable) -> new dictionary initialized as if via:
d = {}
for k, v in iterable:
d[k] = v
dict(**kwargs) -> new dictionary initialized with the name=value pairs
in the keyword argument list. For example: dict(one=1, two=2)
# (copied from class doc)
"""
pass
def __iter__(self, *args, **kwargs): # real signature unknown
""" Implement iter(self). """
pass
def __len__(self, *args, **kwargs): # real signature unknown
""" Return len(self). """
pass
def __le__(self, *args, **kwargs): # real signature unknown
""" Return self<=value. """
pass
def __lt__(self, *args, **kwargs): # real signature unknown
""" Return self<value. """
pass
@staticmethod # known case of __new__
def __new__(*args, **kwargs): # real signature unknown
""" Create and return a new object. See help(type) for accurate signature. """
pass
def __ne__(self, *args, **kwargs): # real signature unknown
""" Return self!=value. """
pass
def __repr__(self, *args, **kwargs): # real signature unknown
""" Return repr(self). """
pass
def __setitem__(self, *args, **kwargs): # real signature unknown
""" Set self[key] to value. """
pass
def __sizeof__(self): # real signature unknown; restored from __doc__
""" D.__sizeof__() -> size of D in memory, in bytes """
pass
__hash__ = None
常用的功能代码示例：
dct = dict({'k1':'jack','k2':12,'k3':'male'})
>>> {'k2': 12, 'k1': 'jack', 'k3': 'male'}
dct.clear()
>>> {}
dct = dict({'k1':'jack','k2':12,'k3':'male'})
dct.get('k2')
>>> 12
dct.items()
dict_items([('k2', 12), ('k1', 'jack'), ('k3', 'male')])
dct.keys()
dict_keys(['k2', 'k1', 'k3'])
dct.values()
dict_values([12, 'jack', 'male'])
dct.pop('k3')
>>> 'male'
dct.popitem()
>>> ('k2', 12)
>>> {'k1': 'jack'}
dct['k2'] = 12
>>> {'k2': 12, 'k1': 'jack'}
len(dct)
set内部功能
集合set()是一个无序且不重合的元素(‘键‘，key)集合，类似于字典，但是没有’值‘，value。
如：
x = set(['a','b','c'])
>>> {'b', 'c', 'a'}
type(x)
>>> <class 'set'>
y = {'aa','bb','cc'}
>>> {'aa', 'cc', 'bb'}
type(y)
>>> <class 'set'>
具体如下：
class set(object):
"""
set() -> new empty set object
set(iterable) -> new set object
Build an unordered collection of unique elements.
"""
def add(self, *args, **kwargs): # real signature unknown
#添加
"""
Add an element to a set.
This has no effect if the element is already present.
"""
pass
def clear(self, *args, **kwargs): # real signature unknown
""" Remove all elements from this set. """
pass
def copy(self, *args, **kwargs): # real signature unknown
""" Return a shallow copy of a set. """
pass
def difference(self, *args, **kwargs): # real signature unknown
#求差集，返回的是old set中的差值元素
"""
Return the difference of two or more sets as a new set.
(i.e. all elements that are in this set but not the others.)
"""
pass
def difference_update(self, *args, **kwargs): # real signature unknown
#删除当前set中的所有包含在 new set 里的元素
""" Remove all elements of another set from this set. """
pass
def discard(self, *args, **kwargs): # real signature unknown
"""
Remove an element from a set if it is a member.
If the element is not a member, do nothing.
"""
pass
def intersection(self, *args, **kwargs): # real signature unknown
#取交集，新创建一个set
"""
Return the intersection of two sets as a new set.
(i.e. all elements that are in both sets.)
"""
pass
def intersection_update(self, *args, **kwargs): # real signature unknown
#取交集，修改原来set
""" Update a set with the intersection of itself and another. """
pass
def isdisjoint(self, *args, **kwargs): # real signature unknown
""" Return True if two sets have a null intersection. """
pass
def issubset(self, *args, **kwargs): # real signature unknown
""" Report whether another set contains this set. """
pass
def issuperset(self, *args, **kwargs): # real signature unknown
""" Report whether this set contains another set. """
pass
def pop(self, *args, **kwargs): # real signature unknown
"""
Remove and return an arbitrary set element.
Raises KeyError if the set is empty.
"""
pass
def remove(self, *args, **kwargs): # real signature unknown
"""
Remove an element from a set; it must be a member.
If the element is not a member, raise a KeyError.
"""
pass
def symmetric_difference(self, *args, **kwargs): # real signature unknown
#对称差集，也就是两边差值元素都会取到，创建新对象
"""
Return the symmetric difference of two sets as a new set.
(i.e. all elements that are in exactly one of the sets.)
"""
pass
def symmetric_difference_update(self, *args, **kwargs): # real signature unknown
#对称差集，也就是两边差值元素都会取到，但只是改变原来对象
""" Update a set with the symmetric difference of itself and another. """
pass
def union(self, *args, **kwargs): # real signature unknown
#并集
"""
Return the union of sets as a new set.
(i.e. all elements that are in either set.)
"""
pass
def update(self, *args, **kwargs): # real signature unknown
""" Update a set with the union of itself and others. """
pass
常见功能代码示例：
x = {'a','b','c','d'}
y = {'a','c','11','22'}
x.difference_update(y)
x
>>> {'d', 'b'}
x = {'a','b','c','d'}
y = {'a','c','11','22'}
z = x.intersection(y)
z
>>> {'c', 'a'}
x.intersection_update(y)
x
>>> {'c', 'a'}
x = {'a','b','c','d'}
y = {'a','c','11','22'}
z = x.symmetric_difference(y)
z
>>> {'11', 'b', '22', 'd'}
x.symmetric_difference_update(y)
x
>>> {'d', '22', '11', 'b'}
下面是一个集合set()实际应用的例子:
# 数据库中原有
old_dict = {
"#1": {'hostname': 'c1', 'cpu_count': 2, 'mem_capicity': 80},
"#2": {'hostname': 'c1', 'cpu_count': 2, 'mem_capicity': 80},
"#3": {'hostname': 'c1', 'cpu_count': 2, 'mem_capicity': 80}
}
# cmdb 新汇报的数据
new_dict = {
"#1": {'hostname': 'c1', 'cpu_count': 2, 'mem_capicity': 800},
"#3": {'hostname': 'c1', 'cpu_count': 2, 'mem_capicity': 80},
"#4": {'hostname': 'c2', 'cpu_count': 2, 'mem_capicity': 80}
}
'''
需要删除：？
需要新建：？
需要更新：？ 注意：无需考虑内部元素是否改变，只要原来存在，新汇报也存在，就是需要更新
'''
# 根据key值来判断；
# old,new两者交集，表示这部分内容需要保持不变，或者更新
# old,new两者差集，表示这部分old内容需要删除
# 注意！这里不用symmetric_difference()方法，而用difference()方法
# new，old两者差集，表示需要添加这部分new内容
old_keylst = old_dict.keys()
new_keylst = new_dict.keys()
old_keyset = set(old_keylst)
new_keyset = set(new_keylst)
need_update_or_reserve = old_keyset.intersection(new_keyset)
need_del = old_keyset.difference(new_keyset)
need_add = new_keyset.difference(old_keyset)
print('need update or reserve:%s\nneed delete:%s\nneed add:%s'%(need_update_or_reserve,need_del,need_add))
集合set()相关的运算符：
1.“ - ”，求差集
2.“ & ”，求交集
3.“ | ”，求并集
4.“ ！= ”，不等于
5.“ == ”，等于
例如，在爬虫时往往因网络问题需要设计断点续传的程序，这时就可以利用集合set()间的运算来实现：
db_urls = [item['url'] for item in url_list.find()] # 用列表解析式装入所有要爬取的链接 index_urls = [item['url'] for item in item_info.find()] # 所引出详情信息数据库中所有的现存的 url 字段 x = set(db_urls) # 转换成集合的数据结构 y = set(index_urls) rest_of_urls = x-y # 相减
collections模块
计数器Counter
计数器Counter是对字典的补充，继承了字典的类。除了计数器Counter自己的内部功能外，也能使用字典的内部功能。
如：
import collections
obj = collections.Counter('dasdasdasfsafassadas')
print(obj)
>>> Counter({'a': 7, 's': 7, 'd': 4, 'f': 2})
计数器Couter内部功能：
class Counter(dict):
'''Dict subclass for counting hashable items. Sometimes called a bag
or multiset. Elements are stored as dictionary keys and their counts
are stored as dictionary values.
>>> c = Counter('abcdeabcdabcaba') # count elements from a string
>>> c.most_common(3) # three most common elements
[('a', 5), ('b', 4), ('c', 3)]
>>> sorted(c) # list all unique elements
['a', 'b', 'c', 'd', 'e']
>>> ''.join(sorted(c.elements())) # list elements with repetitions
'aaaaabbbbcccdde'
>>> sum(c.values()) # total of all counts
15
>>> c['a'] # count of letter 'a'
5
>>> for elem in 'shazam': # update counts from an iterable
... c[elem] += 1 # by adding 1 to each element's count
>>> c['a'] # now there are seven 'a'
7
>>> del c['b'] # remove all 'b'
>>> c['b'] # now there are zero 'b'
0
>>> d = Counter('simsalabim') # make another counter
>>> c.update(d) # add in the second counter
>>> c['a'] # now there are nine 'a'
9
>>> c.clear() # empty the counter
>>> c
Counter()
Note: If a count is set to zero or reduced to zero, it will remain
in the counter until the entry is deleted or the counter is cleared:
>>> c = Counter('aaabbc')
>>> c['b'] -= 2 # reduce the count of 'b' by two
>>> c.most_common() # 'b' is still in, but its count is zero
[('a', 3), ('c', 1), ('b', 0)]
'''
# References:
# http://en.wikipedia.org/wiki/Multiset
# http://www.gnu.org/software/smalltalk/manual-base/html_node/Bag.html
# http://www.demo2s.com/Tutorial/Cpp/0380__set-multiset/Catalog0380__set-multiset.htm
# http://code.activestate.com/recipes/259174/
# Knuth, TAOCP Vol. II section 4.6.3
def __init__(*args, **kwds):
'''Create a new, empty Counter object. And if given, count elements
from an input iterable. Or, initialize the count from another mapping
of elements to their counts.
>>> c = Counter() # a new, empty counter
>>> c = Counter('gallahad') # a new counter from an iterable
>>> c = Counter({'a': 4, 'b': 2}) # a new counter from a mapping
>>> c = Counter(a=4, b=2) # a new counter from keyword args
'''
if not args:
raise TypeError("descriptor '__init__' of 'Counter' object "
"needs an argument")
self, *args = args
if len(args) > 1:
raise TypeError('expected at most 1 arguments, got %d' % len(args))
super(Counter, self).__init__()
self.update(*args, **kwds)
def __missing__(self, key):
'The count of elements not in the Counter is zero.'
# Needed so that self[missing_item] does not raise KeyError
return 0
def most_common(self, n=None):
#返回计数次数较多的n组元素(key,count_value)组成的列表
'''List the n most common elements and their counts from the most
common to the least. If n is None, then list all element counts.
>>> Counter('abcdeabcdabcaba').most_common(3)
[('a', 5), ('b', 4), ('c', 3)]
'''
# Emulate Bag.sortedByCount from Smalltalk
if n is None:
return sorted(self.items(), key=_itemgetter(1), reverse=True)
return _heapq.nlargest(n, self.items(), key=_itemgetter(1))
def elements(self):
#计数器中的所有元素，列表形式
#注：此处非所有元素集合，而是包含所有元素集合的迭代器
'''Iterator over elements repeating each as many times as its count.
>>> c = Counter('ABCABC')
>>> sorted(c.elements())
['A', 'A', 'B', 'B', 'C', 'C']
# Knuth's example for prime factors of 1836: 2**2 * 3**3 * 17**1
>>> prime_factors = Counter({2: 2, 3: 3, 17: 1})
>>> product = 1
>>> for factor in prime_factors.elements(): # loop over factors
... product *= factor # and multiply them
>>> product
1836
Note, if an element's count has been set to zero or is a negative
number, elements() will ignore it.
'''
# Emulate Bag.do from Smalltalk and Multiset.begin from C++.
return _chain.from_iterable(_starmap(_repeat, self.items()))
# Override dict methods where necessary
@classmethod
def fromkeys(cls, iterable, v=None):
# There is no equivalent method for counters because setting v=1
# means that no element can have a count greater than one.
raise NotImplementedError(
'Counter.fromkeys() is undefined. Use Counter(iterable) instead.')
def update(*args, **kwds):
#更新计数器，其实就是增加；如果原来没有，则新建，如果有则加一
'''Like dict.update() but add counts instead of replacing them.
Source can be an iterable, a dictionary, or another Counter instance.
>>> c = Counter('which')
>>> c.update('witch') # add elements from another iterable
>>> d = Counter('watch')
>>> c.update(d) # add elements from another counter
>>> c['h'] # four 'h' in which, witch, and watch
4
'''
# The regular dict.update() operation makes no sense here because the
# replace behavior results in the some of original untouched counts
# being mixed-in with all of the other counts for a mismash that
# doesn't have a straight-forward interpretation in most counting
# contexts. Instead, we implement straight-addition. Both the inputs
# and outputs are allowed to contain zero and negative counts.
if not args:
raise TypeError("descriptor 'update' of 'Counter' object "
"needs an argument")
self, *args = args
if len(args) > 1:
raise TypeError('expected at most 1 arguments, got %d' % len(args))
iterable = args[0] if args else None
if iterable is not None:
if isinstance(iterable, Mapping):
if self:
self_get = self.get
for elem, count in iterable.items():
self[elem] = count + self_get(elem, 0)
else:
super(Counter, self).update(iterable) # fast path when counter is empty
else:
_count_elements(self, iterable)
if kwds:
self.update(kwds)
def subtract(*args, **kwds):
#相减，原来的计数器中的每一个元素的数量减去后添加的元素的数量
'''Like dict.update() but subtracts counts instead of replacing them.
Counts can be reduced below zero. Both the inputs and outputs are
allowed to contain zero and negative counts.
Source can be an iterable, a dictionary, or another Counter instance.
>>> c = Counter('which')
>>> c.subtract('witch') # subtract elements from another iterable
>>> c.subtract(Counter('watch')) # subtract elements from another counter
>>> c['h'] # 2 in which, minus 1 in witch, minus 1 in watch
0
>>> c['w'] # 1 in which, minus 1 in witch, minus 1 in watch
-1
'''
if not args:
raise TypeError("descriptor 'subtract' of 'Counter' object "
"needs an argument")
self, *args = args
if len(args) > 1:
raise TypeError('expected at most 1 arguments, got %d' % len(args))
iterable = args[0] if args else None
if iterable is not None:
self_get = self.get
if isinstance(iterable, Mapping):
for elem, count in iterable.items():
self[elem] = self_get(elem, 0) - count
else:
for elem in iterable:
self[elem] = self_get(elem, 0) - 1
if kwds:
self.subtract(kwds)
def copy(self):
'Return a shallow copy.'
return self.__class__(self)
常用功能示例代码：
import collections
# Counter计数器：
# x = collections.Counter('aabbdfkasd')
x = collections.Counter([11,22,33,44,11,33,11])
print(x)
y = x.most_common(4)
print(y)
for i in x.elements():
print(i)
#Counter继承了字典的类，字典的功能Counter也能用
for key,values in x.items():
print(key,values)
#添加和删除
# x.update([11,11,22,'flexion'])
# x.subtract([11,11,22,'flexion'])
print(x)
有序字典OrderDict
字典dict是无序的序列，而列表list是有序的序列，两者结合就形成了有序字典OrderDict，类似于：
for key in list:
print( dict[ key ] )
有序字典OrderDict是对字典dict类型的补充，他记住了字典元素添加的顺序。有序字典OrderDict的功能很多与字典dict相似：
class OrderedDict(dict):
'Dictionary that remembers insertion order'
# An inherited dict maps keys to values.
# The inherited dict provides __getitem__, __len__, __contains__, and get.
# The remaining methods are order-aware.
# Big-O running times for all methods are the same as regular dictionaries.
# The internal self.__map dict maps keys to links in a doubly linked list.
# The circular doubly linked list starts and ends with a sentinel element.
# The sentinel element never gets deleted (this simplifies the algorithm).
# The sentinel is in self.__hardroot with a weakref proxy in self.__root.
# The prev links are weakref proxies (to prevent circular references).
# Individual links are kept alive by the hard reference in self.__map.
# Those hard references disappear when a key is deleted from an OrderedDict.
def __init__(*args, **kwds):
'''Initialize an ordered dictionary. The signature is the same as
regular dictionaries, but keyword arguments are not recommended because
their insertion order is arbitrary.
'''
if not args:
raise TypeError("descriptor '__init__' of 'OrderedDict' object "
"needs an argument")
self, *args = args
if len(args) > 1:
raise TypeError('expected at most 1 arguments, got %d' % len(args))
try:
self.__root
except AttributeError:
self.__hardroot = _Link()
self.__root = root = _proxy(self.__hardroot)
root.prev = root.next = root
self.__map = {}
self.__update(*args, **kwds)
def __setitem__(self, key, value,
dict_setitem=dict.__setitem__, proxy=_proxy, Link=_Link):
'od.__setitem__(i, y) <==> od[i]=y'
# Setting a new item creates a new link at the end of the linked list,
# and the inherited dictionary is updated with the new key/value pair.
if key not in self:
self.__map[key] = link = Link()
root = self.__root
last = root.prev
link.prev, link.next, link.key = last, root, key
last.next = link
root.prev = proxy(link)
dict_setitem(self, key, value)
def __delitem__(self, key, dict_delitem=dict.__delitem__):
'od.__delitem__(y) <==> del od[y]'
# Deleting an existing item uses self.__map to find the link which gets
# removed by updating the links in the predecessor and successor nodes.
dict_delitem(self, key)
link = self.__map.pop(key)
link_prev = link.prev
link_next = link.next
link_prev.next = link_next
link_next.prev = link_prev
link.prev = None
link.next = None
def __iter__(self):
'od.__iter__() <==> iter(od)'
# Traverse the linked list in order.
root = self.__root
curr = root.next
while curr is not root:
yield curr.key
curr = curr.next
def __reversed__(self):
'od.__reversed__() <==> reversed(od)'
# Traverse the linked list in reverse order.
root = self.__root
curr = root.prev
while curr is not root:
yield curr.key
curr = curr.prev
def clear(self):
'od.clear() -> None. Remove all items from od.'
root = self.__root
root.prev = root.next = root
self.__map.clear()
dict.clear(self)
def popitem(self, last=True):
'''od.popitem() -> (k, v), return and remove a (key, value) pair.
Pairs are returned in LIFO order if last is true or FIFO order if false.
'''
if not self:
raise KeyError('dictionary is empty')
root = self.__root
if last:
link = root.prev
link_prev = link.prev
link_prev.next = root
root.prev = link_prev
else:
link = root.next
link_next = link.next
root.next = link_next
link_next.prev = root
key = link.key
del self.__map[key]
value = dict.pop(self, key)
return key, value
def move_to_end(self, key, last=True):
'''Move an existing element to the end (or beginning if last==False).
Raises KeyError if the element does not exist.
When last=True, acts like a fast version of self[key]=self.pop(key).
'''
link = self.__map[key]
link_prev = link.prev
link_next = link.next
link_prev.next = link_next
link_next.prev = link_prev
root = self.__root
if last:
last = root.prev
link.prev = last
link.next = root
last.next = root.prev = link
else:
first = root.next
link.prev = root
link.next = first
root.next = first.prev = link
def __sizeof__(self):
sizeof = _sys.getsizeof
n = len(self) + 1 # number of links including root
size = sizeof(self.__dict__) # instance dictionary
size += sizeof(self.__map) * 2 # internal dict and inherited dict
size += sizeof(self.__hardroot) * n # link objects
size += sizeof(self.__root) * n # proxy objects
return size
update = __update = MutableMapping.update
def keys(self):
"D.keys() -> a set-like object providing a view on D's keys"
return _OrderedDictKeysView(self)
def items(self):
"D.items() -> a set-like object providing a view on D's items"
return _OrderedDictItemsView(self)
def values(self):
"D.values() -> an object providing a view on D's values"
return _OrderedDictValuesView(self)
__ne__ = MutableMapping.__ne__
__marker = object()
def pop(self, key, default=__marker):
'''od.pop(k[,d]) -> v, remove specified key and return the corresponding
value. If key is not found, d is returned if given, otherwise KeyError
is raised.
'''
if key in self:
result = self[key]
del self[key]
return result
if default is self.__marker:
raise KeyError(key)
return default
def setdefault(self, key, default=None):
'od.setdefault(k[,d]) -> od.get(k,d), also set od[k]=d if k not in od'
if key in self:
return self[key]
self[key] = default
return default
@_recursive_repr()
def __repr__(self):
'od.__repr__() <==> repr(od)'
if not self:
return '%s()' % (self.__class__.__name__,)
return '%s(%r)' % (self.__class__.__name__, list(self.items()))
def __reduce__(self):
'Return state information for pickling'
inst_dict = vars(self).copy()
for k in vars(OrderedDict()):
inst_dict.pop(k, None)
return self.__class__, (), inst_dict or None, None, iter(self.items())
def copy(self):
'od.copy() -> a shallow copy of od'
return self.__class__(self)
@classmethod
def fromkeys(cls, iterable, value=None):
'''OD.fromkeys(S[, v]) -> New ordered dictionary with keys from S.
If not specified, the value defaults to None.
'''
self = cls()
for key in iterable:
self[key] = value
return self
def __eq__(self, other):
'''od.__eq__(y) <==> od==y. Comparison to another OD is order-sensitive
while comparison to a regular mapping is order-insensitive.
'''
if isinstance(other, OrderedDict):
return dict.__eq__(self, other) and all(map(_eq, self, other))
return dict.__eq__(self, other)
常用功能示例代码：
import collections
# OrderedDict有序字典
dic = collections.OrderedDict()
dic['k1'] = 'v1'
dic['k2'] = 'v2'
dic['k3'] = 'v3'
print(dic)
# move_to_end()
dic.move_to_end('k1')
print(dic)
ret = dic.popitem()
print(dic,ret) #这个栈是先进先出，同时这里popitem()返回的是item
ret = dic.pop('k2')
print(dic,ret) #这里pop()返回的是对应的value
默认字典defaultdict
默认字典defaultdict是对字典的类型的补充，他默认给字典的值value设置了一个类型。
dic = collections.defaultdict(list)
dic['k1'].append('Tom')
>>> defaultdict(<class 'list'>, {'k1': ['Tom']})
可命名元组namedtuple
在模块collections中并未对namedtuple提供类属型，故使用前应先创建一个类：
#可命名元组namedtuple(),python中并未对其提供具体的类属性，故使用前应先创建一个类
MytupleClass = collections.namedtuple('MytupleClass',['x','y','z'])
#上述语句，创建了一个名为MytupleClass的类
obj = MytupleClass(11,22,33)
print(obj.x)
print(obj.y)
print(obj.z)
# print(help(MytupleClass)) #查看新创建的这个类MytupleClass的function
可命名元组namedtuple继承了元组tuple的类，亦不可修改！
双向队列deque
双向队列deque：
class deque(object):
"""
deque([iterable[, maxlen]]) --> deque object
A list-like sequence optimized for data accesses near its endpoints.
"""
def append(self, *args, **kwargs): # real signature unknown
""" Add an element to the right side of the deque. """
pass
def appendleft(self, *args, **kwargs): # real signature unknown
""" Add an element to the left side of the deque. """
pass
def clear(self, *args, **kwargs): # real signature unknown
""" Remove all elements from the deque. """
pass
def copy(self, *args, **kwargs): # real signature unknown
""" Return a shallow copy of a deque. """
pass
def count(self, value): # real signature unknown; restored from __doc__
""" D.count(value) -> integer -- return number of occurrences of value """
return 0
def extend(self, *args, **kwargs): # real signature unknown
""" Extend the right side of the deque with elements from the iterable """
pass
def extendleft(self, *args, **kwargs): # real signature unknown
""" Extend the left side of the deque with elements from the iterable """
pass
def index(self, value, start=None, stop=None): # real signature unknown; restored from __doc__
"""
D.index(value, [start, [stop]]) -> integer -- return first index of value.
Raises ValueError if the value is not present.
"""
return 0
def insert(self, index, p_object): # real signature unknown; restored from __doc__
""" D.insert(index, object) -- insert object before index """
pass
def pop(self, *args, **kwargs): # real signature unknown
""" Remove and return the rightmost element. """
pass
def popleft(self, *args, **kwargs): # real signature unknown
""" Remove and return the leftmost element. """
pass
def remove(self, value): # real signature unknown; restored from __doc__
""" D.remove(value) -- remove first occurrence of value. """
pass
def reverse(self): # real signature unknown; restored from __doc__
""" D.reverse() -- reverse *IN PLACE* """
pass
def rotate(self, *args, **kwargs): # real signature unknown
""" Rotate the deque n steps to the right (default n=1). If n is negative, rotates left. """
pass
def __add__(self, *args, **kwargs): # real signature unknown
""" Return self+value. """
pass
def __bool__(self, *args, **kwargs): # real signature unknown
""" self != 0 """
pass
def __contains__(self, *args, **kwargs): # real signature unknown
""" Return key in self. """
pass
def __copy__(self, *args, **kwargs): # real signature unknown
""" Return a shallow copy of a deque. """
pass
def __delitem__(self, *args, **kwargs): # real signature unknown
""" Delete self[key]. """
pass
def __eq__(self, *args, **kwargs): # real signature unknown
""" Return self==value. """
pass
def __getattribute__(self, *args, **kwargs): # real signature unknown
""" Return getattr(self, name). """
pass
def __getitem__(self, *args, **kwargs): # real signature unknown
""" Return self[key]. """
pass
def __ge__(self, *args, **kwargs): # real signature unknown
""" Return self>=value. """
pass
def __gt__(self, *args, **kwargs): # real signature unknown
""" Return self>value. """
pass
def __iadd__(self, *args, **kwargs): # real signature unknown
""" Implement self+=value. """
pass
def __imul__(self, *args, **kwargs): # real signature unknown
""" Implement self*=value. """
pass
def __init__(self, iterable=(), maxlen=None): # known case of _collections.deque.__init__
"""
deque([iterable[, maxlen]]) --> deque object
A list-like sequence optimized for data accesses near its endpoints.
# (copied from class doc)
"""
pass
def __iter__(self, *args, **kwargs): # real signature unknown
""" Implement iter(self). """
pass
def __len__(self, *args, **kwargs): # real signature unknown
""" Return len(self). """
pass
def __le__(self, *args, **kwargs): # real signature unknown
""" Return self<=value. """
pass
def __lt__(self, *args, **kwargs): # real signature unknown
""" Return self<value. """
pass
def __mul__(self, *args, **kwargs): # real signature unknown
""" Return self*value.n """
pass
@staticmethod # known case of __new__
def __new__(*args, **kwargs): # real signature unknown
""" Create and return a new object. See help(type) for accurate signature. """
pass
def __ne__(self, *args, **kwargs): # real signature unknown
""" Return self!=value. """
pass
def __reduce__(self, *args, **kwargs): # real signature unknown
""" Return state information for pickling. """
pass
def __repr__(self, *args, **kwargs): # real signature unknown
""" Return repr(self). """
pass
def __reversed__(self): # real signature unknown; restored from __doc__
""" D.__reversed__() -- return a reverse iterator over the deque """
pass
def __rmul__(self, *args, **kwargs): # real signature unknown
""" Return self*value. """
pass
def __setitem__(self, *args, **kwargs): # real signature unknown
""" Set self[key] to value. """
pass
def __sizeof__(self): # real signature unknown; restored from __doc__
""" D.__sizeof__() -- size of D in memory, in bytes """
pass
maxlen = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
"""maximum size of a deque or None if unbounded"""
__hash__ = None
常用功能代码示例：
import collections
que = collections.deque()
que.append('Jack1')
que.appendleft('Tom0')
>>> deque(['Tom0', 'Jack1'])
que.extend(['li2','lin3'])
>>> deque(['Tom0', 'Jack1', 'li2', 'lin3'])
que.count('li2')
>>> 1
que.insert(4,'stphen4')
>>> deque(['Tom0', 'Jack1', 'li2', 'lin3', 'stphen4'])
que.rotate(2) #循环右移n次
>>> deque(['lin3', 'stphen4', 'Tom0', 'Jack1', 'li2'])
队列queue分为单向队列Queue与双向队列deque:
![[python学习笔记]Day2](https://image.shishitao.com:8440/aHR0cDovL2ltYWdlczIwMTUuY25ibG9ncy5jb20vYmxvZy8xMDA2MDgxLzIwMTYwOC8xMDA2MDgxLTIwMTYwODEzMTU0MzQ3Nzk2LTIxMjEyMTg0ODEucG5n.png?w=700&webp=1 "[python学习笔记]Day2")
单向队列Queue
如：
import queue
obj = queue.Queue()
obj.put('jack')
obj.put('lin')
obj.put('tom')
obj.get()
>>> 'jack'
obj.get()
>>> 'lin'
obj.get()#先进先出，后进后出
>>> 'tom'
具体如下：
class Queue:
'''Create a queue object with a given maximum size.
If maxsize is <= 0, the queue size is infinite.
'''
def __init__(self, maxsize=0):
self.maxsize = maxsize
self._init(maxsize)
# mutex must be held whenever the queue is mutating. All methods
# that acquire mutex must release it before returning. mutex
# is shared between the three conditions, so acquiring and
# releasing the conditions also acquires and releases mutex.
self.mutex = threading.Lock()
# Notify not_empty whenever an item is added to the queue; a
# thread waiting to get is notified then.
self.not_empty = threading.Condition(self.mutex)
# Notify not_full whenever an item is removed from the queue;
# a thread waiting to put is notified then.
self.not_full = threading.Condition(self.mutex)
# Notify all_tasks_done whenever the number of unfinished tasks
# drops to zero; thread waiting to join() is notified to resume
self.all_tasks_done = threading.Condition(self.mutex)
self.unfinished_tasks = 0
def task_done(self):
'''Indicate that a formerly enqueued task is complete.
Used by Queue consumer threads. For each get() used to fetch a task,
a subsequent call to task_done() tells the queue that the processing
on the task is complete.
If a join() is currently blocking, it will resume when all items
have been processed (meaning that a task_done() call was received
for every item that had been put() into the queue).
Raises a ValueError if called more times than there were items
placed in the queue.
'''
with self.all_tasks_done:
unfinished = self.unfinished_tasks - 1
if unfinished <= 0:
if unfinished < 0:
raise ValueError('task_done() called too many times')
self.all_tasks_done.notify_all()
self.unfinished_tasks = unfinished
def join(self):
'''Blocks until all items in the Queue have been gotten and processed.
The count of unfinished tasks goes up whenever an item is added to the
queue. The count goes down whenever a consumer thread calls task_done()
to indicate the item was retrieved and all work on it is complete.
When the count of unfinished tasks drops to zero, join() unblocks.
'''
with self.all_tasks_done:
while self.unfinished_tasks:
self.all_tasks_done.wait()
def qsize(self):
#查看并返回队列中的数据个数
'''Return the approximate size of the queue (not reliable!).'''
with self.mutex:
return self._qsize()
def empty(self):
'''Return True if the queue is empty, False otherwise (not reliable!).
This method is likely to be removed at some point. Use qsize() == 0
as a direct substitute, but be aware that either approach risks a race
condition where a queue can grow before the result of empty() or
qsize() can be used.
To create code that needs to wait for all queued tasks to be
completed, the preferred technique is to use the join() method.
'''
with self.mutex:
return not self._qsize()
def full(self):
'''Return True if the queue is full, False otherwise (not reliable!).
This method is likely to be removed at some point. Use qsize() >= n
as a direct substitute, but be aware that either approach risks a race
condition where a queue can shrink before the result of full() or
qsize() can be used.
'''
with self.mutex:
return 0 < self.maxsize <= self._qsize()
def put(self, item, block=True, timeout=None):
'''Put an item into the queue.
If optional args 'block' is true and 'timeout' is None (the default),
block if necessary until a free slot is available. If 'timeout' is
a non-negative number, it blocks at most 'timeout' seconds and raises
the Full exception if no free slot was available within that time.
Otherwise ('block' is false), put an item on the queue if a free slot
is immediately available, else raise the Full exception ('timeout'
is ignored in that case).
'''
with self.not_full:
if self.maxsize > 0:
if not block:
if self._qsize() >= self.maxsize:
raise Full
elif timeout is None:
while self._qsize() >= self.maxsize:
self.not_full.wait()
elif timeout < 0:
raise ValueError("'timeout' must be a non-negative number")
else:
endtime = time() + timeout
while self._qsize() >= self.maxsize:
remaining = endtime - time()
if remaining <= 0.0:
raise Full
self.not_full.wait(remaining)
self._put(item)
self.unfinished_tasks += 1
self.not_empty.notify()
def get(self, block=True, timeout=None):
#取出一个数据，由于单向，故get()无参数
'''Remove and return an item from the queue.
If optional args 'block' is true and 'timeout' is None (the default),
block if necessary until an item is available. If 'timeout' is
a non-negative number, it blocks at most 'timeout' seconds and raises
the Empty exception if no item was available within that time.
Otherwise ('block' is false), return an item if one is immediately
available, else raise the Empty exception ('timeout' is ignored
in that case).
'''
with self.not_empty:
if not block:
if not self._qsize():
raise Empty
elif timeout is None:
while not self._qsize():
self.not_empty.wait()
elif timeout < 0:
raise ValueError("'timeout' must be a non-negative number")
else:
endtime = time() + timeout
while not self._qsize():
remaining = endtime - time()
if remaining <= 0.0:
raise Empty
self.not_empty.wait(remaining)
item = self._get()
self.not_full.notify()
return item
def put_nowait(self, item):
'''Put an item into the queue without blocking.
Only enqueue the item if a free slot is immediately available.
Otherwise raise the Full exception.
'''
return self.put(item, block=False)
def get_nowait(self):
'''Remove and return an item from the queue without blocking.
Only get an item if one is immediately available. Otherwise
raise the Empty exception.
'''
return self.get(block=False)