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Python: Calculate the sum of a list, after mapping each element to a value using a given function

Python List: Exercise - 250 with Solution

Write a Python program to calculate the sum of a list, after mapping each element to a value using the provided function.

  • Use map() with fn to map each element to a value using the provided function.
  • Use sum() to return the sum of the values.

Sample Solution:

Python Code:

def sum_by(lst, fn):
  return sum(map(fn, lst))
print(sum_by([{ 'n': 4 }, { 'n': 2 }, { 'n': 8 }, { 'n': 6 }], lambda v : v['n']))

Sample Output: 

20

Flowchart:

Flowchart: Calculate the sum of a list, after mapping each element to a value using a given function.

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Previous: Write a Python program to get the minimum value of a list, after mapping each element to a value using a given function.
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Python: Tips of the Day

Given a predicate function, fn, and a prop string, this curried function will then take an object to inspect by calling the property and passing it to the predicate:

Example:

def tips_check_prop(fn, prop):
  return lambda obj: fn(obj[prop])
check_age = tips_check_prop(lambda x: x >= 25, 'age')
user = {'name': 'Owen', 'age': 25}

print(check_age(user))

Output:

True

 

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