How can I compare value of one dictionary to another and get that value?

Question

I'm currently parsing through JSON as a quick example this is what it looks like:

Dictionary 1:

data:
    0:
        tag "importanttagone"
        value   233
    1:  
        tag "importanttagtwo"
        value   234

Dictionary 2:

data:
    0:
        name    "Important Tag One"
        tag     "importanttagone"
    1:
        name    "Important Tag Two"
        tag     "importanttagtwo"

So essentially what I want is to display the name and the value associated.

Expected Output:

Name: Important Tag On

Value: 233

Is there a way to compare both tags in the dictionaries and then get the name that's within the same key as the tag?

Could you provide expected output? – Alexey Nov 19 '17 at 20:58 — Alexey, Nov 19 '17 at 20:58
@Alexey My apologies. I added it – Jason Stratter Nov 19 '17 at 21:01 — Jason Stratter, Nov 19 '17 at 21:01

score 1 · Answer 1 · answered Nov 19 '17 at 21:16

1

d1 = {
    "data":{
        0: {
            "tag": "importanttagone",
            "value": 233
        },
        1: {
            "tag": "importanttagtwo",
            "value": 234
        }
    }
}

d2 = {
    "data":{
        0: {
            "tag": "importanttagone",
            "name": "Important Tag One"
        },
        1: {
            "tag": "importanttagtwo",
            "name": "Important Tag Two"
        }
    }
}

d1_flat = {v['tag']: v['value'] for _, v in d1['data'].items()}
d2_flat = {v['tag']: v['name'] for _, v in d2['data'].items()}

result = {}

for k, v in d1_flat.items():
    name = d2_flat.get(k, None)
    if name:
        result[name] = v

print(result)

Output:

{'Important Tag One': 233, 'Important Tag Two': 234}

answered Nov 19 '17 at 21:16

Alexey

409
2
8

I get a: TypeError: list indices must be integers or slices, not str – Jason Stratter Nov 19 '17 at 21:29
`get` gives you `None` for free. No need to write it as a second argument. – Eric Duminil Nov 19 '17 at 21:47
1

Also, if you don't use the dict keys, you simply could use `for v in d1['data'].values()`. Other than that, your solution is more efficient than the others. – Eric Duminil Nov 19 '17 at 21:50

score 0 · Answer 2 · answered Nov 19 '17 at 21:12

0

If the same tags has the same keys in the dicts:

[(d1[key]['name'], d2[key]['value']) for key in d1 if key in d2]

answered Nov 19 '17 at 21:12

barnabas markus

61
7

score 0 · Answer 3 · answered Nov 19 '17 at 21:13

0

compare the two dictionaries maybe element-wise by iteration through both dicts:

for k1 in dict1:
   for k2 in dict2:
      if dict1[k1]['tag'] == dict2[k2]['tag']
         print('Name  : ' + dict[k1]['name'])
         print('Value : ' + dict[k2]['value'])

answered Nov 19 '17 at 21:13

Dorian

1,439
1
11
26

Thanks, but I've tried this before and I always get: ' KeyError: 'tag' ' – Jason Stratter Nov 19 '17 at 21:30
I added ['data'] to the first two lines. for k1 in dict1['data']: for k2 in dict2['data']: but now i get: TypeError: unhashable type: 'dict' – Jason Stratter Nov 19 '17 at 21:45
1

I'm not 100% sure about your dictionary structure. is it like the one explained by @Alexey ? You have 2 dicts, dict1 and dict2 with the same tags? ever considered putting it in one and the same dict, since you are just doubling your necessary memory? – Dorian Nov 19 '17 at 21:50
I'm not exactly sure. Firefox listed it like that, however, Chrome doesn't have those 0,1,2...etc. Is it possible to combine dictionaries that are parsed from the internet? I didn't even think about that. The problem with that is one dictionary has more keys than the other – Jason Stratter Nov 19 '17 at 21:54
have a look at that: https://stackoverflow.com/a/5946359/7813847 same approach as for efficient SQL databases – Dorian Nov 19 '17 at 21:59

Aaditya Ura · Answer 4 · 2017-11-19T22:50:47.647

You can try One line solution :

#data from @Alexey

d1 = {
    "data":{
        0: {
            "tag": "importanttagone",
            "value": 233
        },
        1: {
            "tag": "importanttagtwo",
            "value": 234
        }
    }
}

d2 = {
    "data":{
        0: {
            "tag": "importanttagone",
            "name": "Important Tag One"
        },
        1: {
            "tag": "importanttagtwo",
            "name": "Important Tag Two"
        }
    }
}

print({item.get('value'):sub_item.get('name') for item in d1['data'].values()for sub_item in d2['data'].values()if item.get('tag') in sub_item.values()})

output:

{233: 'Important Tag One', 234: 'Important Tag Two'}

How can I compare value of one dictionary to another and get that value?

4 Answers4