Python JSON

In this chapter we will introduce how to use Python language to encode and decode JSON objects.

Python 2.7 comes with JSON module [official document]

1. The conversion process from python original type to json type, the specific conversion is as follows:

import json

json.dump(obj, fp, skipkeys=False, ensure_ascii=True, check_circular=True, allow_nan=True, cls=None, indent=None, separators=None, encoding="utf-8", default=None, sort_keys=False, **kw)

json.dumps(obj, skipkeys=False, ensure_ascii=True, check_circular=True, allow_nan=True, cls=None, indent=None, separators=None, encoding="utf-8",default=None, sort_keys= False, **kw)

python python json json

------------------------------------------------ --------

dict                                                                                                                                                                       ​at                                                                                                                                    null

>>> import json

>>> json.dumps(['foo', {'bar': ('baz', None, 1.0, 2)}])

'["foo ", {"bar": ["baz", null, 1.0, 2]}]'

>>> f = open('demo.txt','w')

>> ;> json.dump(range(100), f)

# Open demo.txt and you can see

[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 , 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35 , 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60 , 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85 , 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99]

2. The conversion process from json type to python, The specific conversion is as follows:

import json

json.load(fp[, encoding[, cls[, object_hook[, parse_float[, parse_int[, parse_constant[, object_pairs_hook[, **kw]]]] ]]]])

json.loads(s[, encoding[, cls[, object_hook[, parse_float[, parse_int[, parse_constant[, object_pairs_hook[, **kw]]]]]]])

                                                                                                                                                                        D Object Dict

Array List

String Str

Number (int) int

Number (Real) Float

True Trse False False

NULL NONE

GT; & GT; & GT; & GT; & GT; & GT; & GT; import json

>>> json.loads('{"a": 1, "b": 2, "c": 3}') # string to python objects

{u'a': 1, u' c': 3, u'b': 2}

# Contents in 1.txt

[{"a": [1, 2, 3, 4, 5]}, {"b" : [1, 2, 3]}, {"c": ["English", "Chinese"]}]

>>> f = open('1.txt')

> >> json.load(f)

[{u'a': [1, 2, 3, 4, 5]}, {u'b': [1, 2, 3]}, {u' c': [u'English', u'Chinese']}]

Old version of Python environment configuration (users who come with the json module in Python do not need to look at it)

Using Python to encode or decode JSON Before data, we need to install the JSON module first. In this tutorial we will download Demjson and install it:

$tar

JSON function

Function

Description

encode Encode a Python object into a JSON string

decode Decode an encoded JSON string into a Python object

encode

Python encode() Function for encoding Python objects into JSON strings.

Syntax

demjson.encode(self, obj, nest_level=0)

Example

The following example encodes an array into JSON format data:

#! /usr/bin/python

import demjson

data = [ { 'a' : 1, 'b' : 2, 'c' : 3, 'd' : 4, 'e' : 5 } ]

json = demjson.encode(data)

print json

The execution result of the above code is:

[{"a":1,"b":2," c":3,"d":4,"e":5}]

decode

Python can use the demjson.decode() function to decode JSON data. This function returns the data type of the Python field.

Syntax

demjson.decode(self, txt)

Example

The following example shows how Python decodes JSON objects:

#!/usr/bin /python

import demjson

json = '{"a":1,"b":2,"c":3,"d":4,"e":5}';

text = demjson.decode(json)

print text

The above code execution result is:

{u'a': 1, u'c': 3, u'b': 2, u'e': 5, u'd': 4}