Within a programming language, convert a JSON-formatted string to data structure and then back to a string.

See also JSON section of my data formats guide.

JavaScript

No imports needed.

JSON.parse(myString);

JSON.stringify(myObject);

Prettify with indentation.

JSON.stringify(results, null, 4)

In NodeJS on the command-line:

> var package = require('./package.json')
> package.version
"1.0.0"

Ruby

Import a builtin:

require 'json'

JSON.parse my_string

JSON.generate my_object

JSON.pretty_generate my_object

Or on an object. Also needs the import as above to add this method.

my_string.to_json

{:hello => "world"}.to_json
# => "{\"hello\":\"world\"}"

Jekyll

null

Python

Import the builtin.

import json

Object handling

Read from and write to object - note the s in the method name.

my_obj = json.loads(my_string)

my_string = json.dumps(my_obj)

File handling

Read from and write to file - note *no s in the method names.

with open('file.json') as f_in:
    my_obj = json.load(f_in)

with open('file.json', 'w') as f_out:
    json.dumps(my_object, f_out)

Pretty print

Be sure to specify wrapping indentation level at 4 spaces to make the output appear more vertical than horizontal.

print(json.dumps(my_obj, indent=4)

Alternatively, use the pprint built which will also wrap data stuctures for easy reading but does not impose JSON on everything. For example, JSON does not handle datetime object so you’d have to stringify those with str(value) before you convert to JSON.

import pprint

Using a function:

pprint.pprint(my_object)

# Width is in number of characters.
pprint.pprint(my_object, depth=1, width=60)

Using a class:

pp = pprint.PrettyPrinter(width=60, compact=True)
pp.pprint(my_object)

pp = pprint.PrettyPrinter(indent=4)
pp.pprint(my_object)

Flask

A Python library for websites and APIs. It supports templating using HTML files with Liquid syntax, similar to Jekyll.

Depending how you want certain characters to appear, you might use the safe filter.