python中pop()函数的语法与实例

> list1 = [1,2,4,"hello","xy","你好"]
> a = list1.pop()#默认弹出最后一个元素
> print(a，list1)
你好 [1,2,4,"hello","xy"]

> list2 = [1,2,4,"hello","xy","你好"]
> b = list2.pop(3)#弹出列表中第四个元素
> print(b,list2)
hello [1,2,4,"xy","你好“]

> dict1 = {"papa":"xy","sis":"nikki","dude":"cwy"}
> c = dict.pop()#不给定key值报错
Traceback (most recent call last):
 File "<pyshell#2>", line 1, in <module>
  c = dict.pop()
TypeError: unbound method dict.pop() needs an argument

> dict1 = {"papa":"xy","sis":"nikki","dude":"cwy"}
> c = dict1.pop("papa")
> print(c,dict1)
xy {'sis': 'nikki', 'dude': 'cwy'}

> dict2 = {"papa":"xy","sis":"nikki","dude":"cwy"}
> d = dict2.pop("www")#给定键不在字典内时，未设置default值报错
Traceback (most recent call last):
 File "<pyshell#15>", line 1, in <module>
  d = dict2.pop("www")
KeyError: 'www'

> dict2 = {"papa":"xy","sis":"nikki","dude":"cwy"}
> d = dict2.pop("www","不在字典内")
> print(d,dict2)
不在字典内 {'papa': 'xy', 'sis': 'nikki', 'dude': 'cwy'}