Python JSON Object append

Question

I have loaded two json files in Python3.8, and I need to merge the two based on a condition.

Obj1 = [{'account': '223', 'colr': '#555555', 'hash': True},
        {'account': '134', 'colr': '#666666', 'hash': True},
        {'account': '252', 'colr': '#777777', 'hash': True}]

Obj2 = [{'sn': 38796, 'code': 'df', 'id': 199, 'desc': 'jex - #777777- gg2349.252'},
        {'sn': 21949, 'code': 'se', 'id': 193, 'desc': 'jex - #555555 - gf23569'},
        {'sn': 21340, 'code': 'se', 'id': 3, 'desc': 'jex - #666666 - gf635387'}]

# What I am trying to get

Obj3 = [{'sn': 38796, 'code': 'df', 'id': 199, 'desc': 'jex - #777777- gg2349.252', 'account': '252', 'colr': '#777777', 'hash': True},
        {'sn': 21949, 'code': 'se', 'id': 193, 'desc': 'jex - #555555 - gf23569', 'account': '223', 'colr': '#555555', 'hash': True},
        {'sn': 21340, 'code': 'se', 'id': 3, 'desc': 'jex - #666666 - gf635387', 'account': '134', 'colr': '#666666', 'hash': True}]

I have tried from what I can gather everything on SO from append, extend etc but I fall short on the condition.

I need to be able to append elements in Obj1 to Obj2 at their correct place based on a condition that if the colr of Obj1 is mentioned in desc of Obj2 it should append that whole element from Obj1 into the correlated element of Obj2 . Or create a new Obj3 that I can print these updated values from.

What I have tried and looked at thus far Append JSON Object , Append json objects to nested list , Appending json object to existing json object and a few others that also didn't help.

Hope this makes sense and thank you

Answer 1

Something simple like this would work.

for i in range(len(Obj1)):
    for j in range(len(Obj2)):
        if Obj1[i]['colr'] in Obj2[j]['desc']:
            Obj1[i].update(Obj2[j])

print(Obj1)

Answer 2

One approach is to first create a dictionary mapping each color to the JSON element. You can do this as

colr2elem = {elem['colr']: elem for elem in json_obj1}

Then you can see which color to append applying a Regular Expression to the description and update json_obj2 dictionary (merge dictionaries).

import re

for elem2 in json_obj2:
    elem1 = colr2elem.get(re.search('#\d+', elem2['desc']).group(0))
    elem2.update(elem1 if elem1 is not None else {})

Answer 3

Obj1 = [{'account': '223', 'colr': '#555555', 'hash': True},
                 {'account': '134', 'colr': '#666666', 'hash': True},
                 {'account': '252', 'colr': '#777777', 'hash': True}]

Obj2 = [{'sn': 38796, 'code': 'df', 'id': 199, 'desc': 'jex - #777777- gg2349.252'},
             {'sn': 21949, 'code': 'se', 'id': 193, 'desc': 'jex - #555555 - gf23569'},
             {'sn': 21340, 'code': 'se', 'id': 3, 'desc': 'jex - #666666 - gf635387'}]

Obj3 = []
for i in  Obj1:
    for j in Obj2:
        if i["colr"]==j["desc"][6:13] :
            a = {**j,**i}
            Obj3.append(a)
print(Obj3)

Answer 4

You can use element1['colr'] in element2['desc'] to check if elements from the first and second arrays match. Now, you can iterate over the second array and for each of its elements find the corresponding element from the first array by checking this condition:

json_obj3 = []
for element2 in json_obj2:
    for element1 in json_obj1:
        if element1['colr'] in element2['desc']:
            element3 = dict(**element1, **element2)
            json_obj3.append(element3)
            break  # stop inner for loop, because matched element is found

BTW, this can be written as single expression using nested list comprehension :

json_obj3 = [
    dict(**element1, **element2)
    for element1 in json_obj1
    for element2 in json_obj2
    if element1['colr'] in element2['desc']
]