Python map() function

Hi guys In this tutorial, we are going to learn what a map function does in python,

• The map is a built-in function in python.
• The map function (map() ), executes the specific function on each item of an iterable and returns the address of the map object.

Syntax of map() function in Python

Syntax :
output= map(function_name,iter)

Parameters:

• function_name: It is a function to which map passes each element of given iterable.
• Iter: The iter can be a list, set, tuple, etc.
• You will get an output as a list by using list() inbuilt function

Note:.

1.  These two parameters are compulsorily required for the map function to execute.
2.  You can also give two or more iterable as parameters to a map function.

Examples of map() function

Now, let’s understand map function by using an example :

• Example 1:

#print the cubes of numbers passed a parameter in a list

#cube is a function, It is defined in python as follows

def cube(n):
    return (n*n*n)
    
result=map(cube,[2,5,3])
print(list(result))

Output:

[8,125,27]

• Example 2:

# In this program 5 is subtracted from all the elements of number list by using subtract function

def subtract(a):
    return(a-5)
    
number=[25,81,400]
result=map(subtract,number)
print(list(result))

Output:

[20,76,395]

• Example 3 :

# In this program we add each element of number1 and number2 list by using add function

def add(x,y):
    return(x+y)
    
number1=[2,5,4]
number2=[9,1,3]
result=map(add,number1,number2)
print(set(result))

Output:

{11, 6, 7}

Note:

• In the above code, we have given 2 iterable lists (number1, number2) as a parameter to a map function.
• The output we get as a set. Because of the set method used in the print method.

Example 4 :

# In this program concatenation of each element of number1 and number2 tuple done by using concatenate function

def concatenate(x,y):
    return(x+y)
    
number1=("Abhi","Vasu","John")
number2=("Clever","Honest","Polite")
result=map(concatenate,number1,number2)
print(tuple(result))

Output :

('AbhiClever', 'VasuHonest', 'JohnPolite')

• Example 5:

number1=["143","How are you !"]
result=map(list,number1)
print(list(result))

Output :

[['1', '4', '3'], ['H', 'o', 'w', ' ', 'a', 'r', 'e', ' ', 'y', 'o', 'u', ' ', '!']]

Note:

• In the above program, the list function is iterate on each element of the number1 list. Hence each element of number1 gets converted to a list.
• And since we print the result as a list, we get an output as a list.

Also read:

• Higher Order Functions in Python : map, filter, sorted, reduce