在嵌套的Python词典中搜索键

在嵌套的Python词典中搜索键

你近了

idnum = 11# The loop and 'if' are good# You just had the 'break' in the wrong placefor id, idnumber in A.iteritems():    if idnum in idnumber.keys(): # you can skip '.keys()', it's the default       calculate = some_function_of(idnumber[idnum])       break # if we find it we're done looking - leave the loop    # otherwise we continue to the next dictionaryelse:    # this is the for loop's 'else' clause    # if we don't find it at all, we end up here    # because we never broke out of the loop    calculate = your_default_value    # or whatever you want to do if you don't find it

如果您需要知道

11

内部

dict

s中有多少个作为键，则可以：

idnum = 11print sum(idnum in idnumber for idnumber in A.itervalues())

之所以可行，是因为每个密钥只能进入

dict

一次，因此您只需测试密钥是否退出即可。

in

返回

True

或

False

等于

1

和

0

，因此

sum

是的出现次数

idnum

。