2

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

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  • 3
    What's the expected result? And what have you tried so far? Commented Apr 16, 2020 at 20:04
  • What is your expected output and can you update your sample code to contain Obj1, etc Commented Apr 16, 2020 at 20:23
  • 1
    This really has nothing to do with JSON, which is a text-based serialization format. You are working with python objects, dictionaries, lists, strings, etc. Commented Apr 16, 2020 at 20:27
  • Many people I have read refer to these loaded json files as json objects within python even though I can see they are typed as list. Hope this clears that up. ;-) Commented Apr 16, 2020 at 20:30
  • Once you read the JSON into an object, you get a list of dictionary (for each JSON). You then want to create a new dictionary where you add both dictionaries together, then convert it back to a JSON. Commented Apr 16, 2020 at 20:30

4 Answers 4

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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)
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1 Comment

No, it doesn't work as described: "at their correct place based on a condition that if the 'colr' of Obj1 is mentioned in 'desc' of Obj2"
0

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 {})
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3 Comments

This won't work if any 'colr' value has other format than "# + some digits"
But assumming that HTML colors are used (which is probably be the case) can reduce from O(n²) to O(n).
Even with this assumption, it's still wrong — HTML colors can be written e. g. in rgb(0, 100, 255) form. It would be much easier to make assumption about desc format, e. g. match anything between first and second -
0 
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)
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Comments

-1

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']
]
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