python - 获得两个列表之间的差异(Get difference between two lists)

Question

I have two lists in Python, like these:

(我在Python中有两个列表，如下所示：)

temp1 = ['One', 'Two', 'Three', 'Four']
temp2 = ['One', 'Two']

I need to create a third list with items from the first list which aren't present in the second one.

(我需要用第一个列表中的项目创建第二个列表，而第二个列表中没有这些项目。)

From the example I have to get:

(从示例中，我必须得到：)

temp3 = ['Three', 'Four']

Are there any fast ways without cycles and checking?

(有没有循环和检查的快速方法吗？)

  ask by Max Frai translate from so

Answer 1

In [5]: list(set(temp1) - set(temp2))
Out[5]: ['Four', 'Three']

Beware that

(当心)

In [5]: set([1, 2]) - set([2, 3])
Out[5]: set([1]) 

where you might expect/want it to equal set([1, 3]) .

(您可能希望/希望它等于set([1, 3]) 。)

If you do want set([1, 3]) as your answer, you'll need to use set([1, 2]).symmetric_difference(set([2, 3])) .

(如果确实要使用set([1, 3])作为答案，则需要使用set([1, 2]).symmetric_difference(set([2, 3])) 。)