Formatting JSON in Python

Question

What is the simplest way to pretty-print a string of JSON as a string with indentation when the initial JSON string is formatted without extra spaces or line breaks?

Currently I'm running json.loads() and then running json.dumps() with indent=2 on the result. This works, but it feels like I'm throwing a lot of compute down the drain.

Is there a more simple or efficient (built-in) way to pretty-print a JSON string? (while keeping it as valid JSON)

Example

import requests
import json

response = requests.get('http://spam.eggs/breakfast')
one_line_json = response.content.decode('utf-8')
pretty_json = json.dumps(json.loads(response.content), indent=2)

print(f'Original: {one_line_json}')
print(f'Pretty: {pretty_json}')

Output:

Original: {"breakfast": ["spam", "spam", "eggs"]}
Pretty: {
  "breakfast": [
    "spam", 
    "spam", 
    "eggs"
    ]
}

Answer 1

json.dumps(obj, indent=2)比pprint因为更好：

1. 使用相同的加载方法会更快。
2. 它具有相同或相似的简单性。
3. 输出将产生有效的 JSON，而pprint不会。

pprint_vs_dumps.py

import cProfile
import json
import pprint
from urllib.request import urlopen


def custom_pretty_print():
    url_to_read = "https://www.cbcmusic.ca/Component/Playlog/GetPlaylog?stationId=96&date=2018-11-05"
    with urlopen(url_to_read) as resp:
        pretty_json = json.dumps(json.load(resp), indent=2)
    print(f'Pretty: {pretty_json}')


def pprint_json():
    url_to_read = "https://www.cbcmusic.ca/Component/Playlog/GetPlaylog?stationId=96&date=2018-11-05"
    with urlopen(url_to_read) as resp:
        info = json.load(resp)
    pprint.pprint(info)


cProfile.run('custom_pretty_print()')
>>> 71027 function calls (42309 primitive calls) in 0.084 seconds

cProfile.run('pprint_json()')
>>>164241 function calls (140121 primitive calls) in 0.208 seconds

感谢@tobias_k 一路指出我的错误。