python-jsonpath-rw-ext

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Extensions for JSONPath RW

jsonpath-rw-ext extends json-path-rw capabilities by adding multiple extensions. ‘len’ that allows one to get the length of a list. ‘sorted’ that returns a sorted version of a list, ‘arithmetic’ that permits one to make math operation between elements and ‘filter’ to select only certain elements of a list.

Each extensions will be proposed upstream and will stay here only if they are refused.

Quick Start

At the command line:

$ pip install jsonpath-rw-ext

Or, if you have virtualenvwrapper installed:

$ mkvirtualenv jsonpath-rw-ext
$ pip install jsonpath-rw-ext

To replace the jsonpath_rw parser by this one with:

import jsonpath_rw_ext
jsonpath_rw_ext.parse("$.foo").find(...)

Or:

from jsonpath_rw_ext import parser
parser.ExtentedJsonPathParser().parse("$.foo").find(...)

Shortcut functions for getting only the matched values:

import jsonpath_rw_ext as jp
print jp.match('$.cow[*]', {'cow': ['foo', 'bar'], 'fish': 'foobar'})
# prints ['foo', 'bar']

print jp.match1('$.cow[*]', {'cow': ['foo', 'bar'], 'fish': 'foobar'})
# prints 'foo'

The jsonpath classes are not part of the public API, because the name/structure can change when they will be implemented upstream. Only the syntax shouldn’t change.

Extensions

About arithmetic and string

Operations are done with python operators and allows types that python allows, and return [] if the operation can be done due to incompatible types.

When operators are used, a jsonpath must be be fully defined otherwise jsonpath-rw-ext can’t known if the expression is a string or a jsonpath field, in this case it will choice string as type.

Example with data:

{
    'cow': 'foo',
    'fish': 'bar'
}
cow + fish returns cowfish
$.cow + $.fish returns foobar
$.cow + “_” + $.fish returns foo_bar
$.cow + “_” + fish returns foo_fish

About arithmetic and list

Arithmetic can be used against two lists if they have the same size.

Example with data:

{'objects': [
    {'cow': 2, 'cat': 3},
    {'cow': 4, 'cat': 6}
]}
$.objects[*].cow + $.objects[*].cat returns [6, 9]