1.列表推导式书写形式：
[表达式 for 变量 in 列表] 或者 [表达式 for 变量 in 列表 if 条件]
2.举例说明：
#!/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]
结果：
[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.总结：
我觉得就是通过for 语句处理表达式里面的变量，如果还要加条件，就加if条件就可以了。