基础:
#对象.方法() # a=1 # b=a # a=2 # # _a=2423 # # print(a) # print(b) # # print(False and False) # print(False or False) # # print(0 and 2) # print(1 and 2) # print(1 and 0) # # # print(2 in [1,2,3]) # # #字符串 # # #转义符号 # s='Let\'s go' # # print(r"\fsdghlfjdk.") #查找:[:] # s1="hello world" # # print(s1[1:4]) # print(s1[1:4:2]) # print(s1[-1]) # print(s1[:]) # print(s1[:8]) # print(s1[1:-1]) # print(s1[1:]) # print(s1[-3:-1]) #strip():把字符串开头和结尾的空格以及\n #s=" hello\nworld".strip() # s=" hello\nworld\n" # s1=" hello\nworld\n".strip() # s1="**hello\nworld\n***".strip("*") # print(s) # print(s1) #拼接方法 # s="hello"+"world"+"I"+"am"+"python" # print(s) # # print(" ".join(["I","am","world!"])) #分割方法 # s="hello world".split("l",1) # ["he","lo world"] # print(s) #查找字符 # print("hello world".find("a",4)) # # print("hello world".rfind("l")) # # # # print("hello world".index("q")) #替换方法 # s="hello world" # print(s.replace("world","Python")) # print(s) #居中显示 # print("hello world".center(50,"*")) # print("hello world".ljust(50,"*")) #字符串的格式化输出 #%s:字符串 %d:整型 %f:浮点型 # print("hello %s,%s"%("sb","egon")) # print("hello %s, his age is %d"%("sb",35)) # print("hello %s, his age is %.4f"%("sb",35.53452345)) # print("hello {0}, his age is {1}".format("alex",34)) # print("hello {0}, his age is {1}".format(34,"alex")) # # print("hello {name}, his age is {age}".format(age=30,name="wusir")) # # # print("hello {name}, his age is {age}".format_map({"name":"egon","age":1000})) # print("一".isdecimal()) # print("一".isdigit()) # print("壹".isnumeric()) # print("hello world".capitalize()) # print("hello world".title()) # # print("HELLO world".casefold()) # print("HELLO world".lower()) # print("HELLO\tworld") # print("HELLO world".expandtabs()) # "HELLO world".rsplit() # print("HELLO\n wor\nld\n".splitlines()) # print("HELLO\n wor\nld\n".split("\n")) #print("HELLo world".zfill(10)) print(type(None)) # [] # # () # # {} # # # print(bool(-1)) # print(bool([1,])) # print(bool(None)) # # if None: # print("ok")
集合:
#集合set 两个功能:1 去重 2关系测试 # s=set([1,3,"hello"]) # s2={1,2,3} # # print(s) # print(type(s2)) #去重: # l=[1,2,2,34,45] # s="hello" # # print(set(l)) # print(set(s)) # print({{1,2}:"hello"})# set是可变数据类型 # print({[]:"hello"}) # s3={1,2,[1,2]} # set集合内元素一定是不可变数据类型 # print(s3) #关系测试 s1={"hello",1,2,3} s2={1,2,("a","b")} # 求并集 print(s1.union(s2)) print(s1|s2) # 求交集 print(s1.intersection(s2)) print(s1&s2) # 求差集 print(s1.difference(s2))
set
列表:
#创建形式 可迭代对象:能够进行for循环 l=[1,"hello",[4,5],{"name":"egon"}] l2=list([1,23,3]) l3=[1,23,["hello",334],656,77] # print(l2) # print(type(l2)) # # #查:切片[:] # print(l3[-2:]) #增加 # l3.append("yuan") # l3.append(7) # print(l3) # l3.insert(2,"jjj") # print(l3) # # l3.extend([7,8]) # print(l3) # ret=l3.pop(1) # print(ret) # print(l3) # l3.remove(1) # print(l3) # del l3[2] # print(l3) # del l3 # print(l3) #改 赋值操作 # print(id(l3)) # # l3[2][0]="yuan" # l4=[12,3] # # # l4.clear() # # print(l4) # # l4=[] #推荐这种方式 # [1,222,33].count(33) # len # print(len(l3)) # #l5=[3,1,56,34] # l5=["A","a","B"] # # l5.sort(reverse=True) # print(l5) # sorted(l5) # # [1,2,333,4].reverse() # count=0 # for i in [11,22,33]: # print("%s---%s"%(count,i)) # # count+=1 # l=[1,2,333,4] # for i in l: # print(l.index(i),i) # l=[1,2,333,4] # for i ,v in enumerate(l,1): # print(i,v)
list
循环:
# for i in seq: # seq可以是字符串,列表,元组,字典 # pass # # print("ok") # 两个问题: # 1 循环次数有序列的一级元素的个数决定 #item是什么? for item in ["hello",123,[2,3,4]]: if item==123: continue #结束的本次循环 #break # 结束的整个for循环 #print("ok") print(item) else: print("ending for") print("ending") # print(range(10)) # # for i in range(10): # print("ok") # while 条件表达式: # 执行代码 # # while 2>1: # print("ok") # 打印1-100 # i=1 # while i<101: # print(i) # break # i+=1 # # else: # print("ok") # for i in range(1,101): # print(i)
loop
字典:
#d={[1,2,3]:"yuan","name":"egon"}# 键唯一且为不可变数据类型 #d={1:"yuan","name":"egon"}# 键唯一且为不可变数据类型 #查 # print(d["name"]) # # v=d.get("names",None) #推荐 # print(v) # # if not v: # pass #遍历 # for i in "hello": # print(i) #d={1:"yuan","name":"egon"} # for i in d: # #print(i,"----->",d[i]) # print("%s---->%s======"%(i,d[i])) # print(list(d.keys())) # print(d.values()) # print(d.items()) # 1---->"yuan" # "name"---->"egon" #增 d={1:"yuan","name":"egon"} # d["age"]=123 # print(d) # # # #修改 # d[1]=666 # # print(d) #删除 # ret=d.pop(1) # print(ret) # print(d) # d2={"height":123,"sex":"male","name":"alex"} # # d.update(d2) # print(d)
对经常使用的几种类型的常用方法在学习中测试留下的代码,留作纪念。