Python: JSON

The JSON module

The json module lets you convert JSON Data Format to from Python object.

Basically, JavaScript array is Python's list, and JavaScript object is Python's dictionary.

• JSON Data Format

Export to JSON

json.dumps(obj)

Convert Python obj to JSON string.

json.dump(python_obj, file_obj)

Convert Python object to JSON, write to file file_obj.

Example. Python to JSON string

# python object to JSON string

import json

# python tuple
print(json.dumps((1,2,3)))
# [1, 2, 3]

# python list
print(json.dumps([1, 2, "abc"]))
# [1, 2, "abc"]

# python dict
print(json.dumps({"john":3, "mary":4, "joe":5}))
# {"john": 3, "mary": 4, "joe": 5}

# python special values
print(json.dumps([True, False, None]))
# [true, false, null]

Example. Python to JSON file

# Example. Python to JSON file

import json

xdata = {
    "name": "joe",
    "id": 2967637,
    "colors": ["red", "blue"],
    "address": {"city": "NY", "country": "USA"},
}

outfile_path = "xx-sample.json"

# Writing to file
with open(outfile_path, "w", encoding="utf-8") as xfile:
    json.dump(xdata, xfile)

Import from JSON

json.loads(jsonStr)

Convert JSON string into Python.

json.load(jsonStr, file_obj)

Convert JSON file file_obj to Python.

Example. JSON string to Python

# convert JSON string to Python data structure

import json

json_str = '[true, false, null, 2, 1.0, 4.3, {"jane": 49, "joe":72}]'

python_obj = json.loads(json_str)

print(python_obj)
# [True, False, None, 2, 1.0, 4.3, {'jane': 49, 'joe': 72}]

Example. JSON file to Python object

# example of reading JSON from a file

import json

xdata = {"name": "joe", "year": 2026}

json_file_path = "xx.json"

# create a json file
with open(json_file_path, "w", encoding="utf-8") as xfile:
    json.dump(xdata, xfile, indent=4, ensure_ascii=False)

# read a json file
xresult = json.loads(open(json_file_path).read())

print(xresult)
# {'name': 'joe', 'year': 2026}

Example. Pretty Print JSON

You can use the json lib to pretty print nested hash, by giving the argument indent=1.

import json

hh = {3:4,5:6, 7:{9:{8:10},11:12}}

print(json.dumps(hh,indent=1))

# {
#  "3": 4,
#  "5": 6,
#  "7": {
#   "9": {
#    "8": 10
#   },
#   "11": 12
#  }
# }