What is Python Lambda Function? Python Tutorial | Edureka
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The document explains Python lambda functions, which are anonymous, one-time-use functions that can simplify code by being used as inputs or outputs in higher-order functions. It details how to write and utilize lambda functions within user-defined functions and explains their use with filter(), map(), and reduce() functions to manipulate iterables. The syntax of lambda functions is provided along with example usage, demonstrating their efficiency in coding.
![filter()
Used to filter the given iterables(lists, sets, etc) with the help
of another function passed as an argument to test all the
elements to be true or false.
my_list = [2,3,4,5,6,7,8]
new_list = list(filter(lambda a: (a/3 == 2), my_list))
print(new_list)
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![map():
Applies a given function to all the iterables and returns a
new list.
my_list = [2,3,4,5,6,7,8]
new_list = list(map(lambda a: (a/3 != 2), li))
print(new_list)
www.edureka.co/python](https://image.slidesharecdn.com/lambdafunctions-190912124908/85/What-is-Python-Lambda-Function-Python-Tutorial-Edureka-13-320.jpg)
![reduce():
Applies some other function to a list of elements that are
passed as a parameter to it and finally returns a single
value.
from functools import reduce
reduce(lambda a,b: a+b, [23,21,45,98])
www.edureka.co/python](https://image.slidesharecdn.com/lambdafunctions-190912124908/85/What-is-Python-Lambda-Function-Python-Tutorial-Edureka-14-320.jpg)
What is Python Lambda Function? Python Tutorial | Edureka
- 2. ❖ What are Python Lambda functions? ❖ Why are they used? ❖ How to write Anonymous functions? ❖ Lambda functions within user defined functions • filter() • map() ❖ Using Anonymous functions within www.edureka.co/python • reduce() ❖Solving Algebraic expressions using Lambda
- 4. www.edureka.co PythonLambda Functionsare: • Anonymousornameless functions • ‘lambda’isnotaname,butitsakeyword www.edureka.co/python
- 6. Also known as throw- away functions as they are needed just once They are also passed as inputs or returned as outputs of other higher-order functions The body of Lambda functions is written in a single line One-time use I/O of other functions Reduce code size Why are they used? www.edureka.co/python
- 8. A Lambda function is created using the lambda operator lambda arguments: expression lambda : “Specify the purpose” lambda a1…n: “Specify use of a1…n“ lambda a1: “Specify use of a1“ SYNTAX: www.edureka.co/python
- 10. Lambda functions are best used within other higher- order functions Anonymous functions within user defined functions def new_func(x): return(lambda y: x+y) t=new_func(3) u=new_func(2) print(t(3)) print(u(3)) www.edureka.co/python
- 12. filter() Used to filter the given iterables(lists, sets, etc) with the help of another function passed as an argument to test all the elements to be true or false. my_list = [2,3,4,5,6,7,8] new_list = list(filter(lambda a: (a/3 == 2), my_list)) print(new_list) www.edureka.co/python
- 13. map(): Applies a given function to all the iterables and returns a new list. my_list = [2,3,4,5,6,7,8] new_list = list(map(lambda a: (a/3 != 2), li)) print(new_list) www.edureka.co/python
- 14. reduce(): Applies some other function to a list of elements that are passed as a parameter to it and finally returns a single value. from functools import reduce reduce(lambda a,b: a+b, [23,21,45,98]) www.edureka.co/python
- 16. Copyright © 2017, edureka and/or its affiliates. All rights reserved. www.edureka.co