The Map Function

     You have a list of strings that are numbers and you need to get a sumation of those numbers. How can you do that in Python?  Below, I show you three different ways.

Example Code:

nums = [“3”, “8”, “10”, “1”]

# This will not work because the list items are strings, not integers or floats
# print(sum(nums))

# A traditional way of handling this problem
total = 0
for num in nums:
    total += int(num)
    print(“For loop method:”, total)

# A cool Pythonic way of handling the problem is to use a List comprehension
print(“List comprehension method: “, sum([int(num) for num in nums]))

# Using the map function is probably the best way to handle this problem and also very Pythonic
print(“Map method:”, sum(map(int, nums)))

Output:

For loop method: 22
List comprehension method: 22
Map method: 22

    Remember map next time you need to apply a function to each element that is part of an iterable. The syntax is map(function_to_call, iterable). In our example, we called the int function for elements belonging to a list. The result was a map object that contained integer elements, which we could then use as an argument for the sum function.