How to find the maximum “depth” of a python dictionary or JSON object?

Question

I have a json string and I want to know what its maximum depth is. By depth I mean the number of embedded keys. So if one key as 7 \"children\" and know other key had that

Answer 1

Taking a closer look at your Q, you want to get the depth from a JSON string. Here is a function I write:

# This function count list/dict/tuple as levels
def get_json_depth(s):
    d = {"(":")", "[":"]", "{":"}" }
    stack = []
    lefts = d.keys()
    rights = d.values()

    max_depth = 0
    depth = 0
    in_quotes = False

    for c in s:
            if c == '"':
                    in_quotes = not in_quotes
            if not in_quotes:
                    if c in lefts:
                            stack.append(c)
                            depth += 1
                            if depth > max_depth:
                                    max_depth = depth
                    elif c in rights:
                            if not stack:
                                    raise Exception()
                            if c != d[stack.pop()]:
                                    raise Exception()
    return max_depth

But if you don't mind using json.loads(s) to convert it to dictionary, then use @Blorgbeard's recursive function.

Answer 2

Here's one implementation:

def depth(x):
    if type(x) is dict and x:
        return 1 + max(depth(x[a]) for a in x)
    if type(x) is list and x:
        return 1 + max(depth(a) for a in x)
    return 0

Answer 3

You can find the depth using a recursive function like so.

def depth(jsnFile):
    if jsnFile.has_key('children'):
       return 1 +  max([0] + map(depth, jsnFile['children']))
    else:
       return 1

Answer 4

def depth(d):
    if hasattr(d, "values"):
        return 1 + max(map(depth, d.values()))
    if hasattr(d, "__len__") and not hasattr(d, "lower"):
        return 1 + max(map(depth, d))
    return 0