Question

我想用python代码以最简单的方式解决下面的问题：

a = ['one','two','three','four','five','six','seven','eight','nine']
b = ['three','seven','nine']

如何从a：

中仅删除b的元素

我需要一个 - ＆gt;

A=['one', 'two', 'four', 'five', 'six', 'eight']

Answer 1

使用列表推导来构建新列表：

A = [elem for elem in a if elem not in b]

如果您将b设为一个集合，则会更有效：

b = set(b)

因为成员资格测试（in和not in）对于集合而言比对列表要快得多，其中每个包含的项目都必须单独测试。

演示：

>>> a = ['one','two','three','four','five','six','seven','eight','nine']
>>> b = ['three','seven','nine']
>>> b = set(b)
>>> b
set(['seven', 'nine', 'three'])
>>> [elem for elem in a if elem not in b]
['one', 'two', 'four', 'five', 'six', 'eight']

Answer 2

将它们转换为设置并找到差异。

>>> a = ['one','two','three','four','five','six','seven','eight','nine']
>>> b = ['three','seven','nine']
>>> print (list(set(a)-set(b))) #converted to list,since you want the output as list.
['two', 'eight', 'one', 'five', 'six', 'four']
>>>

在Python中删除列表中的一组字符串

2 个答案: