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# Python and Functional programming

Last updated Feb 9, 2024

## # map()

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 (list, tuple etc.)

Syntax :

map(fun, iter)

Parameters :

fun : It is a function to which map passes each element of given iterable.
iter : It is a iterable which is to be mapped.

NOTE : You can pass one or more iterable to the map() function.
Returns :

Returns a list of the results after applying the given function
to each item of a given iterable (list, tuple etc.)

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NOTE : The returned value from map() (map object) then can be passed to functions like list() (to create a list), set() (to create a set) .
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CODE 1

  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45  # Python program to demonstrate working # of map. # Return double of n def addition(n): return n + n # We double all numbers using map() numbers = (1, 2, 3, 4) result = map(addition, numbers) print(list(result)) Output : [2, 4, 6, 8] Â  **CODE 2** We can also use [lambda expressions](https://www.geeksforgeeks.org/python-lambda-anonymous-functions-filter-map-reduce/) with map to achieve above result. # Double all numbers using map and lambda numbers = (1, 2, 3, 4) result = map(lambda x: x + x, numbers) print(list(result)) Output : [2, 4, 6, 8] Â  **CODE 3** # Add two lists using map and lambda numbers1 = [1, 2, 3] numbers2 = [4, 5, 6] result = map(lambda x, y: x + y, numbers1, numbers2) print(list(result)) Output : [5, 7, 9] Â  **CODE 4** # List of strings l = ['sat', 'bat', 'cat', 'mat'] # map() can listify the list of strings individually test = list(map(list, l)) print(test) Output : [['s', 'a', 't'], ['b', 'a', 't'], ['c', 'a', 't'], ['m', 'a', 't']] `

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Origin:
References: Python Pluralsight course - Functional Programming with Python
Created: 2021-12-23