How do I traverse and search a python dictionary?

Question

I have nested dictionaries:

{\'key0\': {\'attrs\': {\'entity\': \'p\', \'hash\': \'34nj3h43b4n3\', \'id\': \'4130\'},
          u\'key1\': {\'attrs\': {\'ent         


        

Answer 1

Since recursion is known to be limited in python (see What is the maximum recursion depth in Python, and how to increase it?) I would rather have a loop based answer to this question, so the answer can be adapted to any level of depth in the dictionary. For that, the function

def walkDict( aDict, visitor, path=() ):
    for  k in aDict:
        if k == 'attrs':
            visitor( path, aDict[k] )
        elif type(aDict[k]) != dict:
            pass
        else:
            walkDict( aDict[k], visitor, path+(k,) )

Can be replaced by:

def walkDictLoop(aDict, visitor, path=()):
    toProcess = [(aDict, path)]
    while toProcess:
        dictNode, pathNode = toProcess.pop(0)
        for k in dictNode:
            if k == 'attrs':
                visitor(pathNode, dictNode[k])
            if isinstance(dictNode[k], dict):
                toProcess.append( (dictNode[k], pathNode+(k,)) )