Python's JSON module

# # 0x00 introduction:

If we are going to pass objects between different programming languages, we have to serialize the object into a standard format, such as xml, but the better way is to serialize it to json, because JSON represents a string that can be read by all languages, easily stored to disk, or transmitted over a Network. JSON is not only a standard format, but also faster than xml, and can be read directly in the Web page, very convenient.


Serialization (serialization): converts the state information of an object into a process that can be stored or transmitted over a network, in the form of json, xml, and so On. Deserialization is the state of the deserialized object that is read from the storage area (JSON,XML) and Re-created.


# # 0x01 Common functions:

# # # Json.dumps method for simple data type encoding


Encoding: converts a Python object encoding into a JSON string

Decoding: converting JSON format string decoding to Python object


Import JSON
data = [{' a ': ' a ', ' b ':(2,4), ' C ': 3.0}] #list对象
Print "data:", repr (data)

data_string = Json.dumps (data)
Print "JSON:", data_string

Output:

DATA: [{' a ': ' a ', ' C ': 3.0, ' B ':(2,4}]
JSON: [{"a": "a", "c": 3.0, "b": [2,4]}]

# # # Json.loads method handles decoding (decoding) conversions of simple data types

You can use the loads method to convert a JSON string into a python object.

Import JSON
data = [{' a ': ' a ', ' b ':(2,4), ' C ': 3.0}] #list对象

data_string = Json.dumps (data)
Print "encoded:", data_string

decoded = Json.loads (data_string)
Print "decoded:", decoded

Print "ORIGINAL:", type (data[0][' b '))
Print "decoded:", type (decoded[0][' b '))

Output:

Encoded: [{"a": "a", "c": 3.0, "b": [2, 4]}]
Decoded: [{u ' a ': u ' a ', u ' c ': 3.0, u ' b ': [2, 4]}]
ORIGINAL: <type ' tuple ' >


# # # Sort_keys is to tell the encoder to sort by dictionary (a to Z) output,



Import JSON
data = [{' a ': ' a ', ' b ':(2, 4), ' C ': 3.0}]
print ' Data: ', repr (data)
unsorted = Json.dumps (data)
print ' JSON: ', json.dumps (data)
print ' SORT: ', json.dumps (data, Sort_keys=true)

Output:

DATA: [{' a ': ' a ', ' C ': 3.0, ' b ': (2, 4)}]
JSON: [{"a": "a", "c": 3.0, "b": [2, 4]}]
SORT: [{"a": "a", "b": [2, 4], "c": 3.0}

The indent parameter is indented according to the data format and is read more clearly:

print ' INDENT: ', json.dumps (data, sort_keys=true, indent=2)

# # JSON format string written to the file stream

Import JSON
Import Tempfile

f = tempfile. Namedtemporaryfile (mode= ' w+ ')
F.write (' [{"a": "a", "c": 3.0, "b": [2, 4]}] ')
F.flush ()
F.seek (0)

Print Json.load (f)

Output:

[{u ' a ': u ' a ', u ' c ': 3.0, u ' b ': [2, 4]}]


# # 0x03 Basic case:

Case 1,

Import JSON
Js=json.loads (' {' "json": "you are my, hello"} ')
Print Json.dumps (js)
Print Json.dumps (js,ensure_ascii=false)

Case 2,

Import JSON
Js=json.loads (' {' "json": "you are my, hello"} ')
Print Json.dumps (js,encoding= "GB2312")
Print Json.dumps (js,encoding= "utf-8")

Case 3,

Import JSON
s = ' [{"name": "bird's nest", "point": {"lat": "39.990", "lng": "116.397"}, "desc": "olympic home"},{"name": "peking University table tennis hall", "point": {"lat": " 39.988 "," LNG ":" 116.315 "}," desc ":" Table Tennis competition Venue "},{" name ":" Beijing Worker Stadium "," Point ": {" lat ":" 39.930 "," LNG ":" 116.446 "}," desc ":" Football match Venue "}] '
Print Type (s)
Locations = Json.loads (s)
Print Type (locations)
#注: Read is the method of json-py.py and minijson.py, and python2.6 started with the Lib library with simplejson.py, which has no read method, but load/loads
The object after print str (len (LOCATIONS)) #因为json. load () is dict type!
For location in Locations:
Print location["name"]
Print location["point" ["lat"]

Case 4,

Import JSON
Json_string= ' {"first_name": "Guido", "last_name": "russum"} '
Print json_string
Print Type (json_string)
Parsed_json=json.loads (json_string)
Print Parsed_json
Print Type (parsed_json)
Print parsed_json[' last_name ']
Print Json.dumps (json_string)
print json.loads (json_string)

Python's JSON module