Remove all occurrences of a value from a list?

Question

In Python remove() will remove the first occurrence of value in a list.

How to remove all occurrences of a value from a list?

This is w

Answer 1

Let

>>> x = [1, 2, 3, 4, 2, 2, 3]

The simplest and efficient solution as already posted before is

>>> x[:] = [v for v in x if v != 2]
>>> x
[1, 3, 4, 3]

Another possibility which should use less memory but be slower is

>>> for i in range(len(x) - 1, -1, -1):
        if x[i] == 2:
            x.pop(i)  # takes time ~ len(x) - i
>>> x
[1, 3, 4, 3]

Timing results for lists of length 1000 and 100000 with 10% matching entries: 0.16 vs 0.25 ms, and 23 vs 123 ms.