Get a list of all keys in nested dictionary

Question

I want to get a list of all keys in a nested dictionary that contains lists and dictionaries.

I currently have this code, but it seems to be missing adding some keys

Answer 1

As it stands, your code ignores keys that lead to list or dict values. Remove the else block in your first for loop, you want to add the key no matter what the value is.

keys_list = []
def get_keys(d_or_l, keys_list):
    if isinstance(d_or_l, dict):
        for k, v in iter(sorted(d_or_l.iteritems())):
            if isinstance(v, list):
                get_keys(v, keys_list)
            elif isinstance(v, dict):
                get_keys(v, keys_list)
            keys_list.append(k)   #  Altered line
    elif isinstance(d_or_l, list):
        for i in d_or_l:
            if isinstance(i, list):
                get_keys(i, keys_list)
            elif isinstance(i, dict):
                get_keys(i, keys_list)
    else:
        print "** Skipping item of type: {}".format(type(d_or_l))
    return keys_list

get_keys({1: 2, 3: 4, 5: [{7: {9: 1}}]}, keys_list) returns [1, 3, 9, 7, 5]

To avoid duplication, you could use a set datatype instead of a list.