列表推导式
例1
1 [ i*i for i in range(10) ]打印如下：
1 >>> [i*i for i in range(10)]
2 [0, 1, 4, 9, 16, 25, 36, 49, 64, 81]相当于：
1 a=[]
2 for i in range(10):
3 b=i*i
4 a.append(b)例2
1 >>> list1 = [(x, y) for x in range(10) for y in range(10) if x%2==0 if y%2!=0]相当于
1 list1 = []
2 for x in range(10):
3 for y in range(10):
4 if x%2 == 0:
5 if y%2 != 0:
6 list1.append((x, y))
