列表推导式

1、所谓的列表推导式，就是指的轻量级循环创建列表：

a = [i for i in range(1,10)]     # [1, 2, 3, 4, 5, 6, 7, 8, 9]

b= [11 for i in range(1,10)]   # [11, 11, 11, 11, 11, 11, 11, 11, 11]

2、在循环的过程中使用 if 来确定 列表中元素的条件

a = [i for i in range(1,10) if i%2==0]     # [2, 4, 6, 8]

c = [i for i in range(1,10) if i%2==0 if i>5]    # [6, 8]

3、2 个 for 循环

a=[(i,j) for i in range(1,5) for j in range(6,10)]

4、3 个 for 循环

a= [(x,y,z) for x in range(2) for y in range(2) for z in range(2)]