python - 如何比较python中的两个列表并返回匹配项(How can I compare two lists in python and return matches)

Question

I want to take two lists and find the values that appear in both.

(我想获取两个列表并找到两者中出现的值。)

a = [1, 2, 3, 4, 5]
b = [9, 8, 7, 6, 5]

returnMatches(a, b)

would return [5] , for instance.

(例如，会返回[5] 。)

  ask by tehryan translate from so

Answer 1

Not the most efficient one, but by far the most obvious way to do it is:

(不是最有效的方法，但到目前为止最明显的方法是：)

>>> a = [1, 2, 3, 4, 5]
>>> b = [9, 8, 7, 6, 5]
>>> set(a) & set(b)
{5}

if order is significant you can do it with list comprehensions like this:

(如果订单很重要，你可以使用这样的列表推导来做到这一点：)

>>> [i for i, j in zip(a, b) if i == j]
[5]

(only works for equal-sized lists, which order-significance implies).

(（仅适用于大小相同的列表，其中含义为重要性）。)