在py中，對象的賦值并不會(huì)copy 對象，而是增加對象的引用，如果確實(shí)需要copy，引用copy.copy/copt.deepcopy

例子:
lis=['a','b','c']

list1=[{'a':'1'},{'a':'2'},{'a':'3'}]
for i in list1:
        i['a']=i['a']+'_5'
        print i
print list1

import copy
list2=[{'a':'1'},{'a':'2'},{'a':'3'}]
for i in list2:
        j=copy.copy(i)
        j['a']=j['a']+'_5'
        print j

print list2

執(zhí)行結(jié)果
{'a': '1_5'}
{'a': '2_5'}
{'a': '3_5'}
[{'a': '1_5'}, {'a': '2_5'}, {'a': '3_5'}]

{'a': '1_5'}
{'a': '2_5'}
{'a': '3_5'}
[{'a': '1'}, {'a': '2'}, {'a': '3'}]