Python's lambda functions are a concise way to return a value from a single expression. They are often used within other functions (Python supports functional programming) and can even be set as the return value.

The general syntax for a lambda function:


        
        
            
                
                
                    lambda arguments: expression

A very basic lambda function that squares x adds one and returns the result:


        
        
            
                
                
                    lambda x: x**2 + 1

Examples

Multiple arguments

To square x and y and return their sum:


        
        
            
                
                
                    a = lambda x,y: x**2 + y**2
a(1,2)
                
            
            5

Input to other functions

To specify a lambda function as an input to map function:


        
        
            
                
                
                    nums = map(lambda x: x**2 + 1, [1, 2, 3])
print(*nums)
                
            
            2 5 10

As return value

To use lambda function as the return value:


        
        
            
                
                
                    def sqrd_plus_n(n):
    return lambda x: x**2 + n

a = sqrd_plus_n(3)   #We set n as 3 (adding 3)
a(2)    #2**2 + 3
                
            
            7

Published by Arthur Yanagisawa

Edited by 0 others

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