Python Lambda Function
Table Of Content:
- What Is A Lambda Function?
- Lambda Function Syntax.
- Examples Of Lambda Function.
- Lambda Function With map( ) Function.
- Lambda Function With filter( ) Function.
(1) What Is A Lambda Function ?
- Lambda functions are user-defined functions in Python, which have only a single statement to execute.
- The Lambda function can have any number of arguments but only one expression, which is evaluated and returned.
- As we know ‘def’ keyword is used to define a normal function, here, the ‘lambda’ keyword is used to define the Lambda function.
- Lambda functions are the nameless function, which means they can be declared without a name.
(2) Lambda Function Syntax.
lambda arguments: expression
- arguments: This function can have any number of arguments.
- expression: but only one expression, which is evaluated and returned.
- Where ever a function object is required as an argument, you can use the Lambda function.
(3) Examples Of Lambda Function.
Example-1: Printing A Number
func = lambda a : print('Number Is:',a)
print(func)
print(func(5))
Output:
<function <lambda> at 0x000001F70A9CC700>
Number Is: 5
Note:
- Here we have created a Lambda function that will print a number.
- As Lambda functions are the nameless function, you need to assign them to some variable to store the function object.
- You can use the function object to call the Lambda function.
Example-2: Square Of A Number
func = lambda n : n * n
func(4)
Output:
16
Example-3: Adding Numbers
func = lambda a,b,c: print(a+b+c)
func(3,4,5)
Output:
12
(4) Using Lambda Function With map() Function.
- As we already know a map( ) function takes a function object as an argument, you can pass a lambda function to it.
Example
numbers = [1,2,3,4,5,6]
cube = lambda n: n * n * n
mapping = map(cube,numbers)
number_cubes = list(mapping)
number_cubes
Output:
[1, 8, 27, 64, 125, 216]
Note:
- Here I am passing the ‘cube’ lambda function to the map( ) function..
(5) Using Lambda Function With filter() Function.
- As we already know a map( ) function takes a function object as an argument, you can pass a lambda function to it.
Example
numbers = [1,2,3,4,5,6,7,8,9,10]
even = lambda n: n % 2 == 0
filtering = filter(even,numbers)
even_num = list(filtering)
even_num
Output:
[2, 4, 6, 8, 10]
Note:
- Here I am passing the ‘cube’ lambda function to the map( ) function.