python字典

字典的get方法适合来查找key在不在字典里

setdefault( key ,value )  如果key在字典里，则不修改，如果key不在字典里，则补充录入

info={'school':'hnust'}c = dict.fromkeys([6,7,8],[1,{'name':'alex'}])print(c)c[7][1]['name']='jack chen'print(c)

结果如下：

{6: [1, {'name': 'alex'}], 7: [1, {'name': 'alex'}], 8: [1, {'name': 'alex'}]}
{6: [1, {'name': 'jack chen'}], 7: [1, {'name': 'jack chen'}], 8: [1, {'name': 'jack chen'}]}

又出现了列表共用现象~~

for i in info: #效率高    print(i,info[i])    for k,v in info.items():#效率低    print(k,v)