Python - comparing JSON data structures.

README.md

Python - comparing JSON data structures

A function compare_json_data(source_data_a,source_data_b), accepting structures populated with data loaded from json.load() and comparing for equality.

Example

$ python compare.py 
Compare JSON result is: True

JSON files a.json and b.json are loaded via load_json() function and structures passed into compare_json_data() for comparison.

a.json

{
	"apple": "value",
	"orange": 12,
	"banana": [1,2,3,"One","Two","Three","Fourth"],
	"grape": false,
	"strawberry": null,
	"carrot": [
		{
			"fourth": "value-two",
			"first": {
				"apple": "value1",
				"orange": "value2"
			},
			"second": "value",
			"third": "another"
		},
		{},
		["One","Two","Three"]
	],
	"pear": {
		"first": "value",
		"second": "another",
		"third": [1,2,3,"One","Two","Three"],
		"fourth": [
			{
				"first": "value",
				"second": "another"
			},
			{}
		]
	}
}

b.json

{
	"apple": "value",
	"orange": 12,
	"banana": [1,2,3,"One","Two","Three","Fourth"],
	"pear": {
		"first": "value",
		"second": "another",
		"third": [1,2,3,"One","Two","Three"],
		"fourth": [
			{
				"second": "another",
				"first": "value"
			},
			{}
		]
	},
	"grape": false,
	"strawberry": null,
	"carrot": [
		{
			"second": "value",
			"third": "another",
			"fourth": "value-two",
			"first": {
				"apple": "value1",
				"orange": "value2"
			}
		},
		{},
		["One","Two","Three"]
	]
}

compare.py

#!/usr/bin/env python

import json


def load_json(file_path):
	# open JSON file and parse contents
	fh = open(file_path,'r')
	data = json.load(fh)
	fh.close()

	return data

def compare_json_data(source_data_a,source_data_b):

	def compare(data_a,data_b):
		# type: list
		if (type(data_a) is list):
			# is [data_b] a list and of same length as [data_a]?
			if (
				(type(data_b) != list) or
				(len(data_a) != len(data_b))
			):
				return False

			# iterate over list items
			for list_index,list_item in enumerate(data_a):
				# compare [data_a] list item against [data_b] at index
				if (not compare(list_item,data_b[list_index])):
					return False

			# list identical
			return True

		# type: dictionary
		if (type(data_a) is dict):
			# is [data_b] a dictionary?
			if (type(data_b) != dict):
				return False

			# iterate over dictionary keys
			for dict_key,dict_value in data_a.items():
				# key exists in [data_b] dictionary, and same value?
				if (
					(dict_key not in data_b) or
					(not compare(dict_value,data_b[dict_key]))
				):
					return False

			# dictionary identical
			return True

		# simple value - compare both value and type for equality
		return (
			(data_a == data_b) and
			(type(data_a) is type(data_b))
		)

	# compare a to b, then b to a
	return (
		compare(source_data_a,source_data_b) and
		compare(source_data_b,source_data_a)
	)

def main():
	# import testing JSON files to Python structures
	a_json = load_json('a.json')
	b_json = load_json('b.json')

	# compare first struct against second
	print('Compare JSON result is: {0}'.format(
		compare_json_data(a_json,b_json)
	))


if (__name__ == '__main__'):
	main()