1 #encoding=utf-8
 2 
 3 
 4 
 5 #反转字典 即key和val互换 
 6 dict1={1:2,3:4,6:7,9:10}
 7 
 8 
 9 print ‘---生成器表达式‘ 
10 def invert_dict(d): 
11 　　return dict((v,k) for k,v in d.iteritems()) 
12 
13 print invert_dict(dict1) 
14 
15 
16 print ‘---列表推导‘ 
17 def invert_dict2(d): 
18 　　return dict([(v,k) for k,v in d.iteritems()]) 
19 
20 print invert_dict2(dict1) 
21 
22 
23 print ‘---itertools 提高大数据效率‘ 
24 from itertools import izip 
25 
26 
27 def invert_dict3(d): 
28 　　return dict(izip(d.itervalues(),d.iterkeys())) 
29 
30 print invert_dict3(dict1)