1.列表推導(dǎo)式書(shū)寫(xiě)形式：
[表達(dá)式?for?變量?in?列表] ? ?或者 ?[表達(dá)式?for?變量?in?列表?if?條件]? 注意中括號(hào)括起來(lái)
2.舉例說(shuō)明：
#!/usr/bin/python
# -*- coding: utf-8 -*-
li = [1,2,3,4,5,6,7,8,9]
print [x**2 for x in li]
print [x**2 for x in li if x>5]
print dict([(x,x*10) for x in li])
print [ (x, y) for x in range(10)??if x % 2 if x > 3 for y in range(10) if y > 7 if y != 8]
vec=[2,4,6]
vec2=[4,3,-9]
sq = [vec[i]+vec2[i]?for i in range(len(vec))]
print sq
print [x*y for x in [1,2,3] for y in [1,2,3]]
testList = [1,2,3,4]
def mul2(x):
? ? ? return x*2
print [mul2(i) for i in testList]
結(jié)果：
[1, 4, 9, 16, 25, 36, 49, 64, 81]
[36, 49, 64, 81]
{1: 10, 2: 20, 3: 30, 4: 40, 5: 50, 6: 60, 7: 70, 8: 80, 9: 90}
[(5, 9), (7, 9), (9, 9)]
[6, 7, -3]
[1, 2, 3, 2, 4, 6, 3, 6, 9]
[2, 4, 6, 8]
3.總結(jié)：
我覺(jué)得就是通過(guò)for 語(yǔ)句處理表達(dá)式里面的變量，如果還要加條件，就加if條件就可以了。
出自https://www.cnblogs.com/yupeng/p/3428556.html，侵刪
