有没有一种简单的方法可以按值删除列表元素?

问题描述：

a = [1, 2, 3, 4]
b = a.index(6)

del a[b]
print(a)

上面显示了以下错误:

Traceback (most recent call last):
  File "D:\zjm_code\a.py", line 6, in <module>
    b = a.index(6)
ValueError: list.index(x): x not in list

所以我必须这样做:

a = [1, 2, 3, 4]

try:
    b = a.index(6)
    del a[b]
except:
    pass

print(a)

但是有没有更简单的方法来做到这一点?

But is there not a simpler way to do this?

答

要删除元素在列表中的首次出现，只需使用list.remove:

To remove an element's first occurrence in a list, simply use list.remove:

>>> a = ['a', 'b', 'c', 'd']
>>> a.remove('b')
>>> print(a)
['a', 'c', 'd']

请注意，它不会删除所有出现的元素.为此，请使用列表理解.

Mind that it does not remove all occurrences of your element. Use a list comprehension for that.

>>> a = [10, 20, 30, 40, 20, 30, 40, 20, 70, 20]
>>> a = [x for x in a if x != 20]
>>> print(a)
[10, 30, 40, 30, 40, 70]