Skip to content
Related Articles

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
Recommended Articles
Page :