THE WORLD'S LARGEST WEB DEVELOPER SITE

Python Tutorial

Python HOME Python Intro Python Get Started Python Syntax Python Comments Python Variables Python Data Types Python Numbers Python Casting Python Strings Python Booleans Python Operators Python Lists Python Tuples Python Sets Python Dictionaries Python If...Else Python While Loops Python For Loops Python Functions Python Lambda Python Arrays Python Classes/Objects Python Inheritance Python Iterators Python Scope Python Modules Python Dates Python JSON Python RegEx Python PIP Python Try...Except Python User Input Python String Formatting

File Handling

Python File Handling Python Read Files Python Write/Create Files Python Delete Files

Machine Learning

Getting Started Mean Median Mode Standard Deviation Percentile Data Distribution Normal Data Distribution Scatter Plot Linear Regression Polynomial Regression Multiple Regression Scale Train/Test Desision Tree

Python MySQL

MySQL Get Started MySQL Create Database MySQL Create Table MySQL Insert MySQL Select MySQL Where MySQL Order By MySQL Delete MySQL Drop Table MySQL Update MySQL Limit MySQL Join

Python MongoDB

MongoDB Get Started MongoDB Create Database MongoDB Create Collection MongoDB Insert MongoDB Find MongoDB Query MongoDB Sort MongoDB Delete MongoDB Drop Collection MongoDB Update MongoDB Limit

Python Reference

Python Overview Python Built-in Functions Python String Methods Python List Methods Python Dictionary Methods Python Tuple Methods Python Set Methods Python File Methods Python Keywords

Module Reference

Random Module Requests Module

Python How To

Remove List Duplicates Reverse a String

Python Examples

Python Examples Python Exercises Python Quiz Python Certificate

Python Lambda


A lambda function is a small anonymous function.

A lambda function can take any number of arguments, but can only have one expression.


Syntax

lambda arguments : expression

The expression is executed and the result is returned:

Example

A lambda function that adds 10 to the number passed in as an argument, and print the result:

x = lambda a : a + 10
print(x(5))
Run example »

Lambda functions can take any number of arguments:

Example

A lambda function that multiplies argument a with argument b and print the result:

x = lambda a, b : a * b
print(x(5, 6))
Run example »

Example

A lambda function that sums argument a, b, and c and print the result:

x = lambda a, b, c : a + b + c
print(x(5, 6, 2))
Run example »


Why Use Lambda Functions?

The power of lambda is better shown when you use them as an anonymous function inside another function.

Say you have a function definition that takes one argument, and that argument will be multiplied with an unknown number:

def myfunc(n):
  return lambda a : a * n

Use that function definition to make a function that always doubles the number you send in:

Example

def myfunc(n):
  return lambda a : a * n

mydoubler = myfunc(2)

print(mydoubler(11))
Run example »

Or, use the same function definition to make a function that always triples the number you send in:

Example

def myfunc(n):
  return lambda a : a * n

mytripler = myfunc(3)

print(mytripler(11))
Run example »

Or, use the same function definition to make both functions, in the same program:

Example

def myfunc(n):
  return lambda a : a * n

mydoubler = myfunc(2)
mytripler = myfunc(3)

print(mydoubler(11))
print(mytripler(11))
Run example »

Use lambda functions when an anonymous function is required for a short period of time.


Test Yourself With Exercises

Exercise:

Create a lambda function that takes one parameter (a) and returns it.

x =    

Start the Exercise