mirror of
https://github.com/kennethreitz/python-guide.git
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Sam Clift
92 lines
2.5 KiB
ReStructuredText
92 lines
2.5 KiB
ReStructuredText
JSON
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===========
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The `json <https://docs.python.org/2/library/json.html>`_ library can read JSON strings into a Python dictionary or array. It can also serialize Python dictionaries or arrays into JSON strings.
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* There are six basic types in JSON: objects, arrays, numbers, strings, booleans, and null.
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* The root element of JSON representation is an object, signified by ``{ ... }``. JSON objects are analogous to Python dictionaries: they have keys which correspond to values.
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* JSON does not use single quotes. JSON exclusively uses double quotes. Using single quotes in the place of double quotes is invalid JSON syntax.
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Parsing JSON
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------------
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The `json <https://docs.python.org/2/library/json.html>`_ libary is imported like this:
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.. code-block:: python
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import json
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Take the following string containing JSON data:
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.. code-block:: python
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json_string = '{"first_name": "Guido", "last_name":"Rossum"}'
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It can be manpulated like this:
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.. code-block:: python
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converted_dict = json.loads(json_string)
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and can now be used as a normal dictionary:
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.. code-block:: python
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converted_dict['first_name']
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As well as converting a JSON string to a dictionary. You can convert a dictionary to JSON:
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.. code-block:: python
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d = {
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'first_name': 'Guido',
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'second_name': 'Rossum'
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}
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print(json.dumps(d))
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"{'first_name':'Guido','last_name':'Rossum'}"
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We can also load a JSON file by using ``json.load`` instead of ``json.loads``:
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.. code-block:: python
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with file('path/to/file.json') as json_file:
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processed_json = json.load(json_file)
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print(processsed_json)
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{u'first_name': u'Guido', u'last_name': u'Rossum'}
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Here's an example of writing directly to a file by using ``json.dump`` instead of ``json.dumps``:
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.. code-block:: python
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with file('path/to/file.json', 'w') as json_file:
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dict = {
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"first_name": "Guido",
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"last_name": "Rossum",
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"middle_name": "Van"
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}
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json.dump(dict, json_file)
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simplejson
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----------
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`simplejson <https://simplejson.readthedocs.org/en/latest/>`_ is the externally maintained development version of the json library.
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simplejson mimics the json standard library, so you can start using simplejson instead of json by importing it under a different name
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Installation
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.. code-block:: python
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pip install simplejson
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Usage
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.. code-block:: python
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import simplejson as json
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simplejson is available so that developers that use an older version of python can use the latest features available in the json lib.
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