列表推导式 

 1 #列表推导式是基于已有列表推算出新列表的方式
 2 #方法一
 3 list1=[(x,y) for x in range(10) for y in range(10) if x%2==0 if y%2!=0]   
 4 #方法二，推导过程
 5 x,y=0,0
 6 list=[(x,y)]
 7 for x in range(10):
 8     for y in range(10):
 9         if (x%2==0) and (y%2!=0):
10             list.append((x,y))
11 print(list)

 

 1 >>> list1=['x','y','z']
 2 >>> list2 =[1,2,3]
 3 >>> list3=[]
 4 >>> for i in list1:
 5     for j in list2:
 6         list3.append((i,j))
 7 
 8         
 9 >>> list3
10 [('x', 1), ('x', 2), ('x', 3), ('y', 1), ('y', 2), ('y', 3), ('z', 1), ('z', 2), ('z', 3)]
11 >>> list4=[(i,j) for i in list1 for j in list2]
12 >>> list4
13 [('x', 1), ('x', 2), ('x', 3), ('y', 1), ('y', 2), ('y', 3), ('z', 1), ('z', 2), ('z', 3)]

 

posted @ 2017-01-31 16:23  道高一尺  阅读(207)  评论(0)    收藏  举报