How to find a particular json value by key?

Question

There is a json like this:

{
  \"P1\": \"ss\",
  \"Id\": 1234,
  \"P2\": {
      \"P1\": \"cccc\"
  },
  \"P3\": [
      {
          \"P1\": \"aaa\"
      }
         


        

Answer 1

My approach to this problem would be different.

As JSON doesn't allow depth first search, so convert the json to a Python Object, feed it to an XML decoder and then extract the Node you are intending to search

from xml.dom.minidom import parseString
import json        
def bar(somejson, key):
    def val(node):
        # Searches for the next Element Node containing Value
        e = node.nextSibling
        while e and e.nodeType != e.ELEMENT_NODE:
            e = e.nextSibling
        return (e.getElementsByTagName('string')[0].firstChild.nodeValue if e 
                else None)
    # parse the JSON as XML
    foo_dom = parseString(xmlrpclib.dumps((json.loads(somejson),)))
    # and then search all the name tags which are P1's
    # and use the val user function to get the value
    return [val(node) for node in foo_dom.getElementsByTagName('name') 
            if node.firstChild.nodeValue in key]

bar(foo, 'P1')
[u'cccc', u'aaa', u'ss']
bar(foo, ('P1','P2'))
[u'cccc', u'cccc', u'aaa', u'ss']