JSON

There are also other programming languages ​​than Python.

Other languages ​​can not work with python code. If you would like to "talk" with such programs - pass them some processing information or to get results from them - you have to pass the information in a simplified form.

Types

Most programming languages ​​have some numbers, some sort of lists, a variety of strings and some variation of dictionaries (or several ways to create dictionaries). And they have a way how to write True, False and None.

These basic types are usually sufficient for information handover in a legible form, although there are not the exact equivalents in all languages (Python has two basic types of numbers - int andfloat). So we will focus on them.

Data encoding

Another problem is data transfer: so for you to be able to write data on disk or transfer via the Internet, it has to be converted to a sequence of bytes (numbers from 0 to 255). Simplified: you have to convert it to a string.

There are plenty of ways to encode data into text. Each way is trying to find the right balance between legibility for people/computers, length of record, security, options and extensibility. We already know the syntax for Python:

{
    'name': 'Anna',
    'city': 'Prague',
    'languages': ['Czech', 'English', 'Python'],
    'age': 26,
}

Another way to write data is [YAML] (http://www.yaml.org/):

name: Anna
city: Prague
languages:
   - Czech
   - English
   - Python
age: 26

Or maybe [Bencode] (http://en.wikipedia.org/wiki/Bencode):

d6: language9: czech11: english6: Pythone4: agei26e6: city4: Prague6: name4: Annae

There are also non-text formats like [Pickle 3] (https://docs.python.org/3/library/pickle.html):

}q(XjménoqXAnnaqXmÄtoqXBrnoqXjazykyq]q(X       ÄeÅ¡tinaqX
                                                          angliÄtinaXPythonq       eXvÄq
K▒u.

Finally, there is also [JSON] (http://json.org/) (Javascript Object Notation), which, for its simplicity, has expanded the most:

{
  "Name": "Anna",
  "City": "Prague",
  "Languages": ["Czech", "English", "Python"],
  "Age": 26
}

JSON in Python

Object encoding in JSON is simple: there is a json module, whose load method retrieves data from the string:

import json

json_string = """
    {
      "name": "Anna",
      "city": "Brno",
      "languages": ["Czech", "English", "Python"],
      "age": 26
    }
"""

data = json.loads(json_string)
print(data)
print(data['city'])

And then there is the dumps method, which decodes the given data and returns a string.

The string that dumps(data) returns is suitable for computer treatment. If you want to read it, it is better to set ensure_ascii = False (so that accented letters are not encoded with\) and indent = 2 (indent with two spaces).

>>> print(json.dumps(data, ensure_ascii = False, indent = 2))
{
  "name": "Anna",
  "city": "Brno",
  "languages": [
    "Czech",
    "English",
    "Python"
  ],
  "age": 26
}

A complete description of json module - including write/read functions directly to/from files - is in the documentation.