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Python map() and lambda() Use Cases and Examples

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 In Python, map() and lambda functions are often used together for functional programming. Here are some examples to illustrate how they work. Python map and lambda top use cases 1. Using map() with lambda The map() function applies a given function to all items in an iterable (like a list) and returns a map object (which can be converted to a list). Example: Doubling Numbers numbers = [ 1 , 2 , 3 , 4 , 5 ] doubled = list ( map ( lambda x: x * 2 , numbers)) print (doubled) # Output: [2, 4, 6, 8, 10] 2. Using map() to Convert Data Types Example: Converting Strings to Integers string_numbers = [ "1" , "2" , "3" , "4" , "5" ] integers = list ( map ( lambda x: int (x), string_numbers)) print (integers) # Output: [1, 2, 3, 4, 5] 3. Using map() with Multiple Iterables You can also use map() with more than one iterable. The lambda function can take multiple arguments. Example: Adding Two Lists Element-wise list1 = [ 1 , 2 , 3 ]
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Python placeholder '_' Perfect Way to Use it

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What is placeholder in Python? The purpose of it is to mask the variable that you don't want to use in a function. In python, you can call the underscore ( _ ) operator placeholder. Below, you'll find how to use single and double placeholders in a function.


Python placeholder


What is placeholder in python

The purpose of placeholder in Python is to mask variables that you don't want to use in a function. So that your code will be readable. Moreover, in future, if you want to use those variables you can replace the placeholders with the names you want.

In This Page

You'll know in three steps how to use placeholder correctly.
  1. Creating a function
  2. Logic to use single placeholder
  3. Logic to use two placeholders

1. Creating a function.


def function_that_returns_multiple_values(x): 
      return x*2, x*3, x+1 
      for i in range(0,5): 
           square, cube, added_one = function_that_returns_multiple_values(i) 
           print(square, cube)

Here, in print, it returns two variables. I will show you how to mask the unused third variable [added_one] in the below example.

2. Logic to use single placeholder


def function_that_returns_multiple_values(x): 
      return x*2, x*3, x+1 
      for i in range(0,5): 
            square, cube, _ = function_that_returns_multiple_values(i) 
            print(square, cube)

3. Logic to use two placeholders

for i in range(0,5): 
     square, _, _ = function_that_returns_multiple_values(i)


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