Python遍历删除list中元素

错误的做法

如果想要一边遍历，一遍删除list中所有元素，下面的做法会有错误：

wordList = ['a', 'b', 'c', 'd', 'e']
for w in wordList:
    print('before ',wordList, w)
    wordList.remove(w)
    print('after ', wordList, w)

结果为：

before  ['a', 'b', 'c', 'd', 'e'] a
after  ['b', 'c', 'd', 'e'] a
before  ['b', 'c', 'd', 'e'] c
after  ['b', 'd', 'e'] c
before  ['b', 'd', 'e'] e
after  ['b', 'd'] e

可见，如果删除了一个元素后，下一个遍历的元素是当前删除元素之后第二个元素。

正确的做法

1.倒叙遍历删除

wordList = ['a', 'b', 'c', 'd', 'e']
for i in range(len(wordList))[::-1]:
    wordList.pop(i)
    print(wordList)

结果：

['a', 'b', 'c', 'd']
['a', 'b', 'c']
['a', 'b']
['a']
[]

2.创建副本

wordList = ['a', 'b', 'c', 'd', 'e']
newList = [i for i in wordList]
for w in newList:
    wordList.remove(w)
    print(wordList)

结果：

['b', 'c', 'd', 'e']
['c', 'd', 'e']
['d', 'e']
['e']
[]