逻辑判断字符串类型，返回布尔值
1. islower
描述：判断所有字符是否为小写
语法：
def islower(self): # real signature unknown; restored from __doc__
"""
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
样例：
name='allen'
result=name.islower() #判断字符都为小写
print(result) True #显示结果
2. isupper
描述：判断所有字符是否为大写
语法：
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
样例：
name='allen'
result=name.isupper() #判断所有字符为大写
print(result) False #显示结果
3. istitle
描述：判断是否为title类型，即第一个字符为大写，其他为小写
语法：
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
样例：
name='Allen'
result=name.istitle() #判断是否为title类型的字符串
print(result) True #显示结果
4. isalpha
描述：判断所有字符是否为字母
语法：
def isalnum(self): # real signature unknown; restored from __doc__
"""
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
样例：
name = 'allen'
result=name.isalpha() #判断所有字符为字母
print(result) True #显示结果
isalpha
5. isdigit
描述：判断所有字符是否为数字
语法：
def isdigit(self): # real signature unknown; restored from __doc__
"""
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
样例：
name = ''
result=name.isdigit() #判断所有字符为数字
print(result) True #显示结果 name = '123abc'
result=name.isdigit() #判断所有字符为数字
print(result) False #显示结果
isdigit
6. isdecimal
描述：判断所有字符是否是十进制数
语法：
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
样例：
name = ''
result=name.isdecimal() #判断所有字符是否是十进制
print(result) True #显示结果 name = '123abc'
result=name.isdecimal() #判断所有字符是否是十进制
print(result) False #显示结果
decimal