How to compare two JSON objects with the same elements in a different order equal

Question

How can I test whether two JSON objects are equal in python  disregarding the order of lists   For example      JSON document a          errors               error    invalid    field    email              error    required    field    name               success   false     JSON document b          success   false       errors               error    required    field    name              error    invalid    field    email             a and b should compare equal  even though the order of the  errors  lists are different

User · Answer

Decode them and compare them as mgilson comment.

Order does not matter for dictionary as long as the keys, and values matches. (Dictionary has no order in Python)

>>> {'a': 1, 'b': 2} == {'b': 2, 'a': 1}
True

But order is important in list; sorting will solve the problem for the lists.

>>> [1, 2] == [2, 1]
False
>>> [1, 2] == sorted([2, 1])
True

>>> a = '{"errors": [{"error": "invalid", "field": "email"}, {"error": "required", "field": "name"}], "success": false}'
>>> b = '{"errors": [{"error": "required", "field": "name"}, {"error": "invalid", "field": "email"}], "success": false}'
>>> a, b = json.loads(a), json.loads(b)
>>> a['errors'].sort()
>>> b['errors'].sort()
>>> a == b
True

Above example will work for the JSON in the question. For general solution, see Zero Piraeus's answer.

User · Answer

For others who d like to debug the two JSON objects  usually  there is a reference and a target   here is a solution you may use  It will list the  quot path quot  of different mismatched ones from target to the reference  level option is used for selecting how deep you would like to look into  show variables option can be turned on to show the relevant variable  def compareJson example json  target json  level -1  show variables False      different variables    parseJSON example json  target json  level level  show variables show variables    return len  different variables     0   different variables  def  parseJSON reference  target  path     level -1  show variables False       if level  gt  0 and len path     level      return          different variables   list       the case that the inputs is a dict  i e  json dict      if isinstance reference  dict       for  key in reference               path   path   key        try           different variables     parseJSON reference  key   target  key    path  level  show variables        except KeyError           record      join     s   str p  for p in  path           if show variables             record        s  lt -- gt  MISSING    str reference  key            different variables append  record      the case that the inputs is a list tuple   elif isinstance reference  list  or isinstance reference  tuple       for index  v in enumerate reference          path   path  index        try           target v   target index           different variables     parseJSON v   target v   path  level  show variables        except IndexError           record      join     s   str p  for p in  path           if show variables             record        s  lt -- gt  MISSING    str v           different variables append  record      the actual comparison about the value  if they are not the same  record it   elif reference    target       record      join     s   str p  for p in path       if show variables         record        s  lt -- gt   s   str reference   str target        different variables append  record     return  different variables

User · Answer

Another way could be to use json dumps X  sort keys True  option   import json a  b   json dumps a  sort keys True   json dumps b  sort keys True  a    b   a normal string comparison   This works for nested dictionaries and lists

User · Answer

You can write your own equals function    dicts are equal if  1  all keys are equal  2  all values are equal lists are equal if  all items are equal and in the same order primitives are equal if a    b   Because you re dealing with json  you ll have standard python types  dict  list  etc   so you can do hard type checking if type obj      dict    etc   Rough example  not tested    def json equals jsonA  jsonB       if type jsonA     type jsonB             not equal         return False     if type jsonA     dict          if len jsonA     len jsonB               return False         for keyA in jsonA              if keyA not in jsonB or not json equal jsonA keyA   jsonB keyA                    return False     elif type jsonA     list          if len jsonA     len jsonB               return False         for itemA  itemB in zip jsonA  jsonB               if not json equal itemA  itemB                   return False     else          return jsonA    jsonB

User · Answer

For the following two dicts  dictWithListsInValue  and  reorderedDictWithReorderedListsInValue  which are simply reordered versions of each other  dictObj     foo    bar    john    doe   reorderedDictObj     john    doe    foo    bar   dictObj2     abc    def   dictWithListsInValue     A      X    dictObj2  dictObj      Y   2     B   dictObj2  reorderedDictWithReorderedListsInValue     B   dictObj2   A      Y   2     X    reorderedDictObj  dictObj2     a     L    M    N   dictWithListsInValue  b     L    M    N   reorderedDictWithReorderedListsInValue   print sorted a items       sorted b items        gives false   gave me wrong result i e  false    So I created my own cutstom ObjectComparator like this   def my list cmp list1  list2       if  list1   len        list2   len               return False      for l in list1          found   False         for m in list2              res   my obj cmp l  m              if  res                   found   True                 break          if  not found               return False      return True   def my obj cmp obj1  obj2       if isinstance obj1  list           if  not isinstance obj2  list                return False         return my list cmp obj1  obj2      elif  isinstance obj1  dict            if  not isinstance obj2  dict                return False         exp   set obj2 keys       set obj1 keys            if  not exp                 print obj1 keys    obj2 keys                return False         for k in obj1 keys                val1   obj1 get k              val2   obj2 get k              if isinstance val1  list                   if  not my list cmp val1  val2                        return False             elif isinstance val1  dict                   if  not my obj cmp val1  val2                        return False             else                  if val2    val1                      return False     else          return obj1    obj2      return True   dictObj     foo    bar    john    doe   reorderedDictObj     john    doe    foo    bar   dictObj2     abc    def   dictWithListsInValue     A      X    dictObj2  dictObj      Y   2     B   dictObj2  reorderedDictWithReorderedListsInValue     B   dictObj2   A      Y   2     X    reorderedDictObj  dictObj2     a     L    M    N   dictWithListsInValue  b     L    M    N   reorderedDictWithReorderedListsInValue   print my obj cmp a  b      gives true   which gave me the correct expected output   Logic is pretty simple   If the objects are of type  list  then compare each item of the first list with the items of the second list until found   and if the item is not found after going through the second list   then  found  would be   false   found  value is returned  Else if the objects to be compared are of type  dict  then compare the values present for all the respective keys in both the objects   Recursive comparison is performed   Else simply call obj1    obj2   It by default works fine for the object of strings and numbers and for those eq   is defined appropriately     Note that the algorithm can further be improved by removing the items found in object2  so that the next item of object1 would not compare itself with the items already found in the object2

User · Answer

If you want two objects with the same elements but in a different order to compare equal  then the obvious thing to do is compare sorted copies of them - for instance  for the dictionaries represented by your JSON strings a and b   import json  a   json loads            errors               error    invalid    field    email              error    required    field    name               success   false         b   json loads            success   false       errors               error    required    field    name              error    invalid    field    email                     gt  gt  gt  sorted a items       sorted b items    False       but that doesn t work  because in each case  the  errors  item of the top-level dict is a list with the same elements in a different order  and sorted   doesn t try to sort anything except the  top  level of an iterable   To fix that  we can define an ordered function which will recursively sort any lists it finds  and convert dictionaries to lists of  key  value  pairs so that they re orderable    def ordered obj       if isinstance obj  dict           return sorted  k  ordered v   for k  v in obj items        if isinstance obj  list           return sorted ordered x  for x in obj      else          return obj   If we apply this function to a and b  the results compare equal    gt  gt  gt  ordered a     ordered b  True

[python] How to compare two JSON objects with the same elements in a different order equal?

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