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Python – Binary operation on specific keys in Dictionary List
• Last Updated : 04 May, 2020

Sometimes, while working with Python dictionaries, we can have a problem in which we need to perform certain operations over some keys in dictionary throughout the list and return the result. This kind of problem is common in domains involving data like web development. Let’s discuss certain ways in which this task can be performed.

Input : test_list = [{‘best’: 8, ‘Gfg’: 13}, {‘is’: 5, ‘for’: 9, ‘best’: 15, ‘Gfg’: 7, ‘geeks’: 7}]
Output : [(0, 104), (1, 105)]

Input : test_list = [{‘Gfg’ : 3, ‘best’ : 10}]
Output : [(0, 30)]

Method #1 : loop + `enumerate()`
The combination of above functions can be used to solve this problem. This is a brute force approach in which we loop through each dictionary list and perform operation and store result.

 `# Python3 code to demonstrate working of ``# Binary operation on specific keys in Dictionary List``# Using loop + enumerate()`` ` `# initializing list``test_list ``=` `[{``'Gfg'` `: ``5``, ``'is'` `: ``6``, ``'best'` `: ``7``, ``'for'` `: ``8``, ``'geeks'` `: ``10``},``             ``{``'Gfg'` `: ``9``, ``'is'` `: ``4``, ``'best'` `: ``10``, ``'for'` `: ``4``, ``'geeks'` `:``7``},``             ``{``'Gfg'` `: ``2``, ``'is'` `: ``10``, ``'best'` `: ``8``, ``'for'` `: ``9``, ``'geeks'` `: ``3``}]`` ` `# printing original list``print``(``"The original list is : "` `+` `str``(test_list))`` ` `# initializing keys ``op1_key ``=` `'Gfg'``op2_key ``=` `'best'`` ` `# Binary operation on specific keys in Dictionary List``# Using loop + enumerate()``res ``=` `[]``for` `idx, val ``in` `enumerate``(test_list):``    ``res.append((idx, val[op1_key] ``*` `val[op2_key]))`` ` `# printing result ``print``(``"The constructed result list : "` `+` `str``(res)) `
Output :

The original list is : [{‘geeks’: 10, ‘for’: 8, ‘Gfg’: 5, ‘is’: 6, ‘best’: 7}, {‘geeks’: 7, ‘for’: 4, ‘Gfg’: 9, ‘is’: 4, ‘best’: 10}, {‘geeks’: 3, ‘for’: 9, ‘Gfg’: 2, ‘is’: 10, ‘best’: 8}]

The constructed result list : [(0, 35), (1, 90), (2, 16)]

Method #2 : Using list comprehension + `enumerate()`
The combination of above functions can also be used to solve this problem. In this, we perform similar task using list comprehension in shorthand manner.

 `# Python3 code to demonstrate working of ``# Binary operation on specific keys in Dictionary List``# Using list comprehension + enumerate()`` ` `# initializing list``test_list ``=` `[{``'Gfg'` `: ``5``, ``'is'` `: ``6``, ``'best'` `: ``7``, ``'for'` `: ``8``, ``'geeks'` `: ``10``},``             ``{``'Gfg'` `: ``9``, ``'is'` `: ``4``, ``'best'` `: ``10``, ``'for'` `: ``4``, ``'geeks'` `:``7``},``             ``{``'Gfg'` `: ``2``, ``'is'` `: ``10``, ``'best'` `: ``8``, ``'for'` `: ``9``, ``'geeks'` `: ``3``}]`` ` `# printing original list``print``(``"The original list is : "` `+` `str``(test_list))`` ` `# initializing keys ``op1_key ``=` `'Gfg'``op2_key ``=` `'best'`` ` `# Binary operation on specific keys in Dictionary List``# Using list comprehension + enumerate()``res ``=` `[(idx, val[op1_key] ``*` `val[op2_key]) ``for` `idx, val ``in` `enumerate``(test_list)]`` ` `# printing result ``print``(``"The constructed result list : "` `+` `str``(res)) `
Output :

The original list is : [{‘geeks’: 10, ‘for’: 8, ‘Gfg’: 5, ‘is’: 6, ‘best’: 7}, {‘geeks’: 7, ‘for’: 4, ‘Gfg’: 9, ‘is’: 4, ‘best’: 10}, {‘geeks’: 3, ‘for’: 9, ‘Gfg’: 2, ‘is’: 10, ‘best’: 8}]

The constructed result list : [(0, 35), (1, 90), (2, 16)]

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