Related Articles

# Python – Dictionary Values Mapped Summation

• Last Updated : 07 Apr, 2021

Given a dictionary with a values list, our task is to extract the sum of values, found using mappings.

Input : test_dict = {4 : [‘a’, ‘v’, ‘b’, ‘e’],

1 : [‘g’, ‘f’, ‘g’],

3 : [‘e’, ‘v’]}, map_vals = {‘a’ : 3, ‘g’ : 8, ‘f’ : 10, ‘b’ : 4, ‘e’ : 7, ‘v’ : 2}

Output : {4: 16, 1: 26, 3: 9}

Explanation : “g” has 8, “f” has 10 as magnitude, hence 1 is mapped by 8 + 8 + 10 = 26. ( sum of list mapped ).

Input : test_dict = {4 : [‘a’, ‘v’, ‘b’, ‘e’],

1 : [‘g’, ‘f’, ‘g’]}, map_vals = {‘a’ : 3, ‘g’ : 8, ‘f’ : 10, ‘b’ : 4, ‘e’ : 7, ‘v’ : 2}

Output : {4: 16, 1: 26}

Explanation : “g” has 8, “f” has 10 as magnitude, hence 1 is mapped by 8 + 8 + 10 = 26. ( sum of list mapped ).

Method 1 : Using loop + items()

In this, each key is iterated in the dictionary and each value of each dict. is iterated and summed using mapped sum dictionary initialized.

## Python3

 `# Python3 code to demonstrate working of``# Dictionary Values Mapped Summation``# Using loop + items()`` ` `# initializing dictionary``test_dict ``=` `{``4` `: [``'a'``, ``'v'``, ``'b'``, ``'e'``],``             ``1` `: [``'g'``, ``'f'``, ``'g'``],``             ``3` `: [``'e'``, ``'v'``]}``              ` `# printing original dictionary``print``(``"The original dictionary is : "` `+` `str``(test_dict))`` ` `# values mapped ``map_vals ``=` `{``'a'` `: ``3``, ``'g'` `: ``8``, ``'f'` `: ``10``,``            ``'b'` `: ``4``, ``'e'` `: ``7``, ``'v'` `: ``2``}`` ` `res ``=` `dict``()``# items() getting keys and values``for` `key, vals ``in` `test_dict.items():``    ``sum` `=` `0``    ``for` `val ``in` `vals:``         ` `        ``# summing with mappings``        ``sum` `+``=` `map_vals[val]``    ``res[key] ``=` `sum`` ` `# printing result``print``(``"The extracted values sum : "` `+` `str``(res))`

Output:

The original dictionary is : {4: [‘a’, ‘v’, ‘b’, ‘e’], 1: [‘g’, ‘f’, ‘g’], 3: [‘e’, ‘v’]}

The extracted values sum : {4: 16, 1: 26, 3: 9}

Method #2 : Using dictionary comprehension + sum()

In this, we perform the task of getting sum of each value using sum(). The dictionary comprehension is used for getting keys and assigning to values sum corresponding in shorthand.

## Python3

 `# Python3 code to demonstrate working of``# Dictionary Values Mapped Summation``# Using dictionary comprehension + sum()`` ` `# initializing dictionary``test_dict ``=` `{``4` `: [``'a'``, ``'v'``, ``'b'``, ``'e'``],``             ``1` `: [``'g'``, ``'f'``, ``'g'``],``             ``3` `: [``'e'``, ``'v'``]}``              ` `# printing original dictionary``print``(``"The original dictionary is : "` `+` `str``(test_dict))`` ` `# values mapped ``map_vals ``=` `{``'a'` `: ``3``, ``'g'` `: ``8``, ``'f'` `: ``10``,``            ``'b'` `: ``4``, ``'e'` `: ``7``, ``'v'` `: ``2``}`` ` `# sum() gets sum of each mapped values ``res ``=` `{key : ``sum``(map_vals[val] ``for` `val ``in` `vals) ``       ``for` `key, vals ``in` `test_dict.items()}`` ` `# printing result``print``(``"The extracted values sum : "` `+` `str``(res))`

Output:

The original dictionary is : {4: [‘a’, ‘v’, ‘b’, ‘e’], 1: [‘g’, ‘f’, ‘g’], 3: [‘e’, ‘v’]}

The extracted values sum : {4: 16, 1: 26, 3: 9}

Attention geek! Strengthen your foundations with the Python Programming Foundation Course and learn the basics.

To begin with, your interview preparations Enhance your Data Structures concepts with the Python DS Course. And to begin with your Machine Learning Journey, join the Machine Learning – Basic Level Course

My Personal Notes arrow_drop_up