How to loop through a JSON object?

Question

I want to loop through an arbitrary JSON object in Python and get all values. I do not know what the JSON object looks like. I just want to loop through all elements. So also through the child objects and lists. I have now taken an arbitrary JSON object from the Internet to test. But it could also be any other JSON object. Currently I try it like this:

def printJSONVals(json_object): 
 it = iter(json_object)
 n = json_object[next(it)]
 while n is not None:
 print n
 n = json_object[next(it)]
json_obj = json.loads('{ "city" : "AGAWAM", "loc" : [ -72.622739, 42.070206 ], "pop" : 15338, "state" : "MA", "_id" : "01001"}')
printJSONVals(json_obj)

Unfortunately, this does not work, because I get the list "loc" back as a list and not the individual values. Is there a way to loop through a JSON object regardless of the depth of the nesting and always store the value of the individual keys in the variable n?

As a result, I want the variable n to always contain the values of the keys. Regardless of the depth of the nesting of the object. So I expect this output here:

AGAWAM
-72.622739
42.070206
15338
MA
01001

I would like to write these later in a two-dimensional array. But this is not important. It is enough if I manage to output the values independent of the nesting.

I use Python version 2.7.17

Thank you

• jarmod: What problem are you actually trying to solve?
• Ali: I want to create a two-dimensional array, which always contains the following data: ("key", "parent", "val")
• Laurent LAPORTE: What do you mean by "parent"?
• Laurent LAPORTE: meta.stackoverflow.com/questions/253162/…
• chepner: json_obj is not a "JSON object". It's a dict. JSON stopped being relevant as soon as json.loads returned.

Answer 1

Well, you can use dict keys to calculate the path of ancestors.

import json
def print_json(obj, parent=None):
 if isinstance(obj, list):
 for child in obj:
 for path, item in print_json(child, parent):
 yield path, item
 elif isinstance(obj, dict):
 for key, child in obj.iteritems(): # items() in Python3
 child_path = [key] if parent is None else parent + [key]
 for path, item in print_json(child, child_path):
 yield path, item
 else:
 yield parent, obj

With you example, you have:

json_obj = json.loads(
 '{ "city" : "AGAWAM", "loc" : [ -72.622739, 42.070206 ], "pop" : 15338, "state" : "MA", "_id" : "01001"}'
)
for path, item in print_json(json_obj):
 print(path, ":", item)

The result:

['city'] : AGAWAM
['loc'] : -72.622739
['loc'] : 42.070206
['pop'] : 15338
['state'] : MA
['_id'] : 01001

Another example:

json_obj = json.loads(
 '{ "city" : "AGAWAM", "loc" : { "type": "int", "value": 16}}'
)

You get:

['city'] : AGAWAM
['loc', 'type'] : int
['loc', 'value'] : 16