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Diffstat (limited to 'Doc/library/json.rst')
| -rw-r--r-- | Doc/library/json.rst | 103 |
1 files changed, 100 insertions, 3 deletions
diff --git a/Doc/library/json.rst b/Doc/library/json.rst index a01e636..d62f14b 100644 --- a/Doc/library/json.rst +++ b/Doc/library/json.rst @@ -106,6 +106,8 @@ Using json.tool from the shell to validate and pretty-print:: $ echo '{1.2:3.4}' | python -m json.tool Expecting property name enclosed in double quotes: line 1 column 2 (char 1) +See :ref:`json-commandline` for detailed documentation. + .. highlight:: python3 .. note:: @@ -248,7 +250,7 @@ Basic Usage will be passed to the constructor of the class. If the data being deserialized is not a valid JSON document, a - :exc:`ValueError` will be raised. + :exc:`JSONDecodeError` will be raised. .. function:: loads(s, encoding=None, cls=None, object_hook=None, parse_float=None, parse_int=None, parse_constant=None, object_pairs_hook=None, **kw) @@ -259,7 +261,7 @@ Basic Usage *encoding* which is ignored and deprecated. If the data being deserialized is not a valid JSON document, a - :exc:`ValueError` will be raised. + :exc:`JSONDecodeError` will be raised. Encoders and Decoders --------------------- @@ -332,13 +334,16 @@ Encoders and Decoders ``'\n'``, ``'\r'`` and ``'\0'``. If the data being deserialized is not a valid JSON document, a - :exc:`ValueError` will be raised. + :exc:`JSONDecodeError` will be raised. .. method:: decode(s) Return the Python representation of *s* (a :class:`str` instance containing a JSON document). + :exc:`JSONDecodeError` will be raised if the given JSON document is not + valid. + .. method:: raw_decode(s) Decode a JSON document from *s* (a :class:`str` beginning with a @@ -467,6 +472,36 @@ Encoders and Decoders mysocket.write(chunk) +Exceptions +---------- + +.. exception:: JSONDecodeError(msg, doc, pos, end=None) + + Subclass of :exc:`ValueError` with the following additional attributes: + + .. attribute:: msg + + The unformatted error message. + + .. attribute:: doc + + The JSON document being parsed. + + .. attribute:: pos + + The start index of *doc* where parsing failed. + + .. attribute:: lineno + + The line corresponding to *pos*. + + .. attribute:: colno + + The column corresponding to *pos*. + + .. versionadded:: 3.5 + + Standard Compliance and Interoperability ---------------------------------------- @@ -588,6 +623,68 @@ when serializing Python :class:`int` values of extremely large magnitude, or when serializing instances of "exotic" numerical types such as :class:`decimal.Decimal`. +.. highlight:: bash +.. module:: json.tool + +.. _json-commandline: + +Command Line Interface +---------------------- + +The :mod:`json.tool` module provides a simple command line interface to validate +and pretty-print JSON objects. + +If the optional ``infile`` and ``outfile`` arguments are not +specified, :attr:`sys.stdin` and :attr:`sys.stdout` will be used respectively:: + + $ echo '{"json": "obj"}' | python -m json.tool + { + "json": "obj" + } + $ echo '{1.2:3.4}' | python -m json.tool + Expecting property name enclosed in double quotes: line 1 column 2 (char 1) + +.. versionchanged:: 3.5 + The output is now in the same order as the input. Use the + :option:`--sort-keys` option to sort the output of dictionaries + alphabetically by key. + +Command line options +^^^^^^^^^^^^^^^^^^^^ + +.. cmdoption:: infile + + The JSON file to be validated or pretty-printed:: + + $ python -m json.tool mp_films.json + [ + { + "title": "And Now for Something Completely Different", + "year": 1971 + }, + { + "title": "Monty Python and the Holy Grail", + "year": 1975 + } + ] + + If *infile* is not specified, read from :attr:`sys.stdin`. + +.. cmdoption:: outfile + + Write the output of the *infile* to the given *outfile*. Otherwise, write it + to :attr:`sys.stdout`. + +.. cmdoption:: --sort-keys + + Sort the output of dictionaries alphabetically by key. + + .. versionadded:: 3.5 + +.. cmdoption:: -h, --help + + Show the help message. + .. rubric:: Footnotes |