recursion - Recursive depth of python dictionary

Question

G'day,

I am trying to find the recursive depth of a function that trawls a dictionary and I'm a bit lost... Currently I have something like:

myDict = {'leve1_key1': {'level2_key1': {'level3_key1': {'level4_key_1': {'level5_key1':   'level5_value1'}}}}}

And I want to know just how nested the most nested dictionary is... so I do the following...

def dict_depth(d, depth):

    for i in d.keys():
        if type(d[i]) is dict:
            newDict = d[i]
            dict_depth(newDict, depth+1)
    return depth

print dict_depth(myDict, 0)

Only problem is, the recursive loop only returns the return of the final value (0). if I put in a print statement for i in d.keys(): then I can at least print the highest value of recursion, but returning the value is a different matter...

I'm sure this is straightforward - I've just got jellybrain.

Cheers

Answer 1

Be sure to assign the result of the recursive call to depth. Also, as @amit says, consider using max so that you can handle dicts with multiple key value pairs (a treelike structure).

def dict_depth(d, depth=0):
    if not isinstance(d, dict) or not d:
        return depth
    return max(dict_depth(v, depth+1) for k, v in d.iteritems())

>>> myDict = {'leve1_key1': {'level2_key1': 
               {'level3_key1': {'level4_key_1': 
                  {'level5_key1':   'level5_value1'}}}}}
>>> dict_depth(myDict)
5