Search for a key in a nested Python dictionary

dictionary, nested, python, recursion

Solution

You're close.

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:

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. `in` returns `True` or `False` which are equal to `1` and `0`, so the `sum` is the number of occurences of `idnum`.

Problem

I have some Python dictionaries like this: ``` A = {id: {idnumber: condition},.... ``` e.g. ``` 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`. But if in the entire dictionary doesn't have any `idnumber == 11`, I need to continue with the next dictionary. This is my try: ``` for id, idnumber in A.iteritems(): if 11 in idnumber.keys(): calculate = ...... else: break ```

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