[Dynamic Language] Python 列表推导

时间：2010-12-11 来源：※ABeen※

列表推导相当于通过重复调用结果列表的append方法建立相同列表的for循环。

演示：

l  = [1,2,3,4,5,6]
result1 = [x+1 for x in l]
相当于以下代码:
result2 = []
for x in l :
    result2.append(x+1)


result3 = [x+1 for x in l if x > 3]
相当于以下代码:
result4 = []
for x in l:
    if x > 3:
        result4.append(x+1)


l2 = [4,5,6]
result5 = [x+y for x in l if x>4 for y in l2 if y>5]
相当于以下代码:
result6 = []
for x in l:
    if x > 4:
        for y in l2:
            if y > 5:
                result6.append(x+y)