Package: jsonpath-rw
https://github.com/kennknowles/python-jsonpath-rwThis library provides a robust and significantly extended implementation
of JSONPath for Python. It is tested with Python 2.6, 2.7, 3.2, 3.3.(On travis-ci there is a segfault when running the tests with pypy; I don’t think the problem lies with this library).This library differs from other JSONPath implementations in that it is a
fulllanguageimplementation, meaning the JSONPath expressions are
first class objects, easy to analyze, transform, parse, print, and
extend. (You can also execute them :-)Quick StartTo install, use pip:$ pip install jsonpath-rwThen:$python>>>fromjsonpath_rwimportjsonpath,parse# A robust parser, not just a regex. (Makes powerful extensions possible; see below)>>>jsonpath_expr=parse('foo[*].baz')# Extracting values is easy>>>[match.valueformatchinjsonpath_expr.find({'foo':[{'baz':1},{'baz':2}]})][1,2]# Matches remember where they came from>>>[str(match.full_path)formatchinjsonpath_expr.find({'foo':[{'baz':1},{'baz':2}]})]['foo.[0].baz','foo.[1].baz']# And this can be useful for automatically providing ids for bits of data that do not have them (currently a global switch)>>>jsonpath.auto_id_field='id'>>>[match.valueformatchinparse('foo[*].id').find({'foo':[{'id':'bizzle'},{'baz':3}]})]['foo.bizzle','foo.[1]']# A handy extension: named operators like `parent`>>>[match.valueformatchinparse('a.*.b.`parent`.c').find({'a':{'x':{'b':1,'c':'number one'},'y':{'b':2,'c':'number two'}}})]['number two','number one']# You can also build expressions directly quite easily>>>fromjsonpath_rw.jsonpathimportFields>>>fromjsonpath_rw.jsonpathimportSlice>>>jsonpath_expr_direct=Fields('foo').child(Slice('*')).child(Fields('baz'))# This is equivalentJSONPath SyntaxThe JSONPath syntax supported by this library includes some additional
features and omits some problematic features (those that make it
unportable). In particular, some new operators such as|andwhereare available, and parentheses are used for grouping not for
callbacks into Python, since with these changes the language is not
trivially associative. Also, fields may be quoted whether or not they
are contained in brackets.Atomic expressions:SyntaxMeaning$The root object`this`The “current” object.`foo`More generally, this syntax allows “named operators” to extend JSONPath is arbitrary waysfieldSpecified field(s), described below[field]Same asfield[idx]Array access, described below (this is always unambiguous with field access)Jsonpath operators:SyntaxMeaningjsonpath1.jsonpath2All nodes matched byjsonpath2starting at any node matchingjsonpath1jsonpath[whatever]Same asjsonpath.whateverjsonpath1..jsonpath2All nodes matched byjsonpath2that descend from any node matchingjsonpath1jsonpath1wherejsonpath2Any nodes matchingjsonpath1with a child matchingjsonpath2jsonpath1|jsonpath2Any nodes matching the union ofjsonpath1andjsonpath2Field specifiers (field):SyntaxMeaningfieldnamethe fieldfieldname(from the “current” object)"fieldname"same as above, for allowing special characters in the fieldname'fieldname'ditto*any fieldfield,fieldeither of the named fields (you can always build equivalent jsonpath using|)Array specifiers (idx):SyntaxMeaning[n]array index (may be comma-separated list)[start?:end?]array slicing (note thatstepis unimplemented only due to lack of need thus far)[*]any array indexProgrammatic JSONPathIf you are programming in Python and would like a more robust way to
create JSONPath expressions that does not depend on a parser, it is very
easy to do so directly, and here are some examples:Root()Slice(start=0, end=None, step=None)Fields('foo','bar')Index(42)Child(Fields('foo'),Index(42))Where(Slice(),Fields('subfield'))Descendants(jsonpath, jsonpath)ExtensionsPath data: The result ofJsonPath.findprovide detailed context
and path data so it is easy to traverse to parent objects, print full
paths to pieces of data, and generate automatic ids.Automatic Ids: If you setjsonpath_rw.auto_id_fieldto a value
other than None, then for any piece of data missing that field, it
will be replaced by the JSONPath to it, giving automatic unique ids
to any piece of data. These ids will take into account any ids
already present as well.Named operators: Instead of using@to reference the currently
object, this library uses`this`. In general, any string
contained in backquotes can be made to be a new operator, currently
by extending the library.More to exploreThere are way too many jsonpath implementations out there to discuss.
Some are robust, some are toy projects that still work fine, some are
exercises. There will undoubtedly be many more. This one is made for use
in released, maintained code, and in particular for programmatic access
to the abstract syntax and extension. But JSONPath at its simplest just
isn’t that complicated, so you can probably use any of them
successfully. Why not this one?The original proposal, as far as I know:JSONPath - XPath for
JSONby Stefan Goessner.Special note about PLY and docstringsThe main parsing toolkit underlying this library,PLY, does not work with docstrings
removed. For example,PYTHONOPTIMIZE=2andpython-OOwill both
cause a failure.ContributorsThis package is authored and maintained by:Kenn Knowles(@kennknowles)with the help of patches submitted bythese contributors.Copyright and LicenseCopyright 2013- Kenneth KnowlesLicensed under the Apache License, Version 2.0 (the “License”); you may
not use this file except in compliance with the License. You may obtain
a copy of the License athttp://www.apache.org/licenses/LICENSE-2.0Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an “AS IS” BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.