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Python map() Function with Examples

Learn about the map() function, its usages, syntax, and examples.
Submitted by IncludeHelp, on March 06, 2022

In Python programming language, the map() function is a built-in function that is used to process and transform all the items in an iterable (list, tuple, dict, set) without using a for a loop. The map() function returns a map object (which is an iterator) of the results after applying the given function to each item of a given iterable.

Syntax for map() function:

map(function, iterable_type)

Parameter(s):

• function: Function for which the map() passes each element of the given iterable.
• iterable_type: It is an iterable type that is to be mapped.

Note: More than one iterables can be passed to the map() function.

Return value of map() function: The map() function returns a list of the results after applying the given function to each item of a given iterable.

Example 1:

# Python program to demonstrate the 
# example of map() function
  
# Function to calculate the square
def square(n):
    return n*n
  
# Using map() - 
# finding the square of all numbers
values = (10, 20, 1, 5, 7)
print("The values: ", values)

squares = map(square, values)

print("The squares: ", list(squares))

Output:

The values:  (10, 20, 1, 5, 7)
The squares:  [100, 400, 1, 25, 49]

Example 2: An example of using of lambda expressions with map

# Python program to demonstrate the 
# example of map() function

# Using map() - 
# finding the square of all numbers
values = (10, 20, 1, 5, 7)
print("The values: ", values)

squares = map(lambda n: n * n, values)

print("The squares: ", list(squares))

Output:

The values:  (10, 20, 1, 5, 7)
The squares:  [100, 400, 1, 25, 49]

Example 3:

# Python program to demonstrate the 
# example of map() function

# Adding two lists using map() and lambda
  
list1 = [10, 20, 30]
list2 = [11, 22, 33]
  
sum_lists = map(lambda m, n: m + n, list1, list2)

print("list1: ", list1)
print("list2: ", list2)
print("sum_lists: ", list(sum_lists))

Output:

list1:  [10, 20, 30]
list2:  [11, 22, 33]
sum_lists:  [21, 42, 63]