[英]Search for a key in a nested Python dictionary
I have some Python dictionaries like this: 我有一些像这样的Python词典:
A = {id: {idnumber: condition},....
eg 例如
A = {1: {11 : 567.54}, 2: {14 : 123.13}, .....
I need to search if the dictionary has any idnumber == 11
and calculate something with the condition
. 我需要搜索字典是否有任何idnumber == 11
并计算具有condition
。 But if in the entire dictionary doesn't have any idnumber == 11
, I need to continue with the next dictionary. 但如果在整个字典中没有任何idnumber == 11
,我需要继续下一个字典。
This is my try: 这是我的尝试:
for id, idnumber in A.iteritems():
if 11 in idnumber.keys():
calculate = ......
else:
break
http://github.com/akesterson/dpath-python http://github.com/akesterson/dpath-python
dpath lets you search by globs, which will get you what you want. dpath让你通过globs搜索,它会得到你想要的。
$ easy_install dpath
>>> for (path, value) in dpath.util.search(MY_DICT, '*/11', yielded=True):
>>> ... # 'value' will contain your condition; now do something with it.
It will iterate out all of the conditions in the dictionary, so no special looping constructs required. 它将迭代字典中的所有条件,因此不需要特殊的循环结构。
You're close. 你很亲密
idnum = 11
# The loop and 'if' are good
# You just had the 'break' in the wrong place
for 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 dictionary
else:
# 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
If you need to know how many 11
s there are as keys in the inner dict
s, you can: 如果您需要知道内部dict
有多少11
秒作为键,您可以:
idnum = 11
print sum(idnum in idnumber for idnumber in A.itervalues())
This works because a key can only be in each dict
once so you just have to test if the key exits. 这是有效的,因为一个键只能在每个dict
一次,所以你只需要测试键是否退出。 in
returns True
or False
which are equal to 1
and 0
, so the sum
is the number of occurences of idnum
. in
返回True
或False
,它们等于1
和0
,因此sum
是idnum
。
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