Xpath like query for nested python dictionaries

Question

Is there a way to define a XPath type query for nested python dictionaries.

Something like this:

foo = {
  \'spam\':\'eggs\',
  \'morefoo\': {
               


        

Answer 1

dict > jmespath

You can use JMESPath which is a query language for JSON, and which has a python implementation.

import jmespath # pip install jmespath

data = {'root': {'section': {'item1': 'value1', 'item2': 'value2'}}}

jmespath.search('root.section.item2', data)
Out[42]: 'value2'

The jmespath query syntax and live examples: http://jmespath.org/tutorial.html

dict > xml > xpath

Another option would be converting your dictionaries to XML using something like dicttoxml and then use regular XPath expressions e.g. via lxml or whatever other library you prefer.

from dicttoxml import dicttoxml  # pip install dicttoxml
from lxml import etree  # pip install lxml

data = {'root': {'section': {'item1': 'value1', 'item2': 'value2'}}}
xml_data = dicttoxml(data, attr_type=False)
Out[43]: b'
value1value2'

tree = etree.fromstring(xml_data)
tree.xpath('//item2/text()')
Out[44]: ['value2']

Json Pointer

Yet another option is Json Pointer which is an IETF spec that has a python implementation:

• https://github.com/stefankoegl/python-json-pointer

From the jsonpointer-python tutorial:

from jsonpointer import resolve_pointer

obj = {"foo": {"anArray": [ {"prop": 44}], "another prop": {"baz": "A string" }}}

resolve_pointer(obj, '') == obj
# True

resolve_pointer(obj, '/foo/another%20prop/baz') == obj['foo']['another prop']['baz']
# True

>>> resolve_pointer(obj, '/foo/anArray/0') == obj['foo']['anArray'][0]
# True