CODEWITHSUNDEEP
python-3.x
hemanta
hemanta

Reputation: 1510

Compare the values between keys of dictionaries in a list and return the one with maximum value and next key on the basis of this value

I have a list that contains a dictionary as its elements. I want to compare the value of a particular key here 'ce_fraction' with the value of the same keys in other dictionary and return the value of key 'ce_symbol' of which the value of 'ce_fraction' is: maximum. For example from the following I need to return 'ce_symbol': 'S:1', as its corresponding value for 'ce_fraction', is maximum between all dictionaries in the list.

d1 = [{'ce_symbol': 'S:1',
   'ce_fraction': 0.9826993502161626,
   'csm': 0.0,
   'permutation': [0]},
  {'ce_symbol': 'ST:7',
   'ce_fraction': 0.01729545180302663,
   'csm': 6.419666329644907,
   'permutation': [3, 1, 4, 6, 0, 5, 2]},
  {'ce_symbol': 'TL:3',
   'ce_fraction': 5.112772362143661e-06,
   'csm': 5.01422215914756,
   'permutation': [0, 1, 2]},
  {'ce_symbol': 'TS:3',
   'ce_fraction': 6.631085890198608e-08,
   'csm': 7.49194295399119,
   'permutation': [0, 2, 1]},
  {'ce_symbol': 'TY:3',
   'ce_fraction': 1.8897589832589626e-08,
   'csm': 7.720504649029379,
   'permutation': [0, 1, 2]}]

I have many such lists and need to do for the one having more than one dictionary as elements in the list. I can print the values and keys in a new list but I need to compare them. Could anyone please help me with this. Thanks in advance.

for i in range(len(d1)):
        ce_frac = []
        symbol = []
        if len(d1[i]) >1:
            for j in range(len(d1[i])):
                    ce_frac.append(d1[j]['ce_fraction'])
                    symbol.append(d1[j]['ce_symbol'])

Upvotes: 0

Views: 57

Answers (2)

Upasana Mittal
Upasana Mittal

Reputation: 2680

from operator import itemgetter

d1 = [{'ce_symbol': 'S:1',
'ce_fraction': 0.9826993502161626,
'csm': 0.0,
'permutation': [0]},
{'ce_symbol': 'ST:7',
'ce_fraction': 0.01729545180302663,
'csm': 6.419666329644907,
'permutation': [3, 1, 4, 6, 0, 5, 2]},
{'ce_symbol': 'TL:3',
'ce_fraction': 5.112772362143661e-06,
'csm': 5.01422215914756,
'permutation': [0, 1, 2]},
{'ce_symbol': 'TS:3',
'ce_fraction': 6.631085890198608e-08,
'csm': 7.49194295399119,
'permutation': [0, 2, 1]},
{'ce_symbol': 'TY:3',
'ce_fraction': 1.8897589832589626e-08,
'csm': 7.720504649029379,
'permutation': [0, 1, 2]}]

lis = [(i["ce_fraction"],i["ce_symbol"]) for i in d1]
max_ce_symbol = min(lis,key=itemgetter(1))[1]

print(max_ce_symbol)

Output

'S:1'

Upvotes: 0

Devesh Kumar Singh
Devesh Kumar Singh

Reputation: 20500

If I take your full example as an input, I would start by making a list of symbol and fractions.

ce_frac = []
symbol = []
for d in d1:
    for item in d:
        ce_frac.append(item['ce_fraction'])
        symbol.append(item['ce_symbol'])

Then I find the maximum value in ce_frac list and find it's index, and the answer is the symbol appearing at that index in symbol list

#Get Maximum value of ce_fraction and find it's index
max_frac = max(ce_frac)
max_idx = ce_frac.index(max_frac)
#It's symbol will be present at the same index in symbol
print(symbol[max_idx])
#S:1

Update
For a faster approach, I have sorted the inner list of all the dictionaries in place on the key ce_fraction, and the first element of your resultant list will be your answer

sorted_list = (sorted(d1[0], key = lambda i: i['ce_fraction'],reverse=True) )
print(sorted_list[0]['ce_symbol'])
#S:1

Upvotes: 1

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