What is lambda in python? Detailed explanation with examples

Everyone who wants to study programming must have heard that python is one of the easiest programming languages out there. Yes, it is. But to be able to grasp most out of it, you need to be aware of what is lambda in python, also called lambda functions.

According to a recent survey of StackOverflow python was one of the most widely used programming languages in 2019.

Programmers are hungry to use it in their projects because of its scalability and usability.

If you are a beginner in programming then learning python may be easy for you in comparison to other programming languages like java, c, c++, and so on.

Introduction to Python

Python is a dynamically typed programming language that means you don’t need to worry about typecasting and declaring variable type.

You can learn its syntaxes and basic concepts in 2 – 3 weeks with very comfortable ease. Oops, concepts will take a little bit of extra time because oops concepts are mainly used in making a variety of scalable applications.

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And now let’s talk about someone who has some experience in oops programming.

If you are coming from an object-oriented programming background (oop) learning python is a piece of cake for you.

You can easily learn its syntax and basics as they are pretty easy as compared to other programming languages out there in the market.

You can learn python within a week. But exploring python libraries may take a little bit of extra time.

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Where can you use Python

Python can be used in so many fields such as data science, machine learning, game development, GUI, desktop applications, web development (flask and Django frameworks), and others.

What is a function?

Before jumping into the lambda function in python lets find out what is a function in the programming world. While making a large program or large software it’s hard to solve a big problem at once.

A function takes input, performs some operations on input, and gives us an output. For example, you can make a function that calculates the average of the given numbers.

Eg. In python, a function looks something like this.

def calculateAvg(a,b,c):

  return a*b*c

Explanation of code :

Here the def is a keyword in python that is used to define a function. And after the def keyword, the name of the function is situated.a,b, and c  are the input parameters of the function.

Return is also a pre-defined keyword that will return the value of a*b*c.

Function calling:

Defining a function is not a complete task. You have to call the function somewhere in your program.

 a =   calculateAvg(3,5,6)

This fun will return the avg of 3,4,5 and we stored in a variable a.

Another reason for the simplicity of python is that it has a lot of built-in functions that can ease your programming journey.

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For Example, here I listed some function that is used in python.

1. The pow() function in python returns the value of A to the power of B.

  a = pow(2,3)

print(a)

Output: 8

2. The open() function in python opens the file and will return the object of the file.

 a = open("samplefile.txt", "r")

print(a.read())

Output: The context of the file 

[ Hello world, This is the text that is written in samplefile.txt]

3. The abs() function in python returns the absolute value of a given number.

    a =  abs(-6.25)

  print(a)

Output :   6.25

4. The bin() function in python returns the binary form of a given number.

 a = bin(45) 

    print(a)

Output : 0b101101

5. The min() function in python return the minimum value

        a= min(1,4,5,6,3,5)

        print(a)

Output : 1

6. The max() function n python returns the maximum number.

  a = max(3,5,6,7,10)

        print (a)

Output: 10

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What is lambda in Python?

In the Python programming language, there are mainly two types of functions

  1. Normal function
  2. Anonymous function

A normal function in python is defined by the keyword def and it has some name also.while an Anonymous function in python does not has a name and defined by using the keyword lambda. An anonymous function is also called the lambda function in python.

Lambda function is a very useful function in python.

You can pass any number of input parameters in lambda function but lambda function consist only one expression.

Syntax of the lambda function:

lambda arguments: expression

For example, here I write a lambda function that adds 20 into the input number.

    a  =  lambda  x  :  x  +  20

        print(a(30)) 

Output: 50

Now I showed you a lambda function that takes only one argument but lambda function can receive multiple arguments.

Example:

1. Here x, y is the input parameters and, x*y is the actual expression of the lambda function.

a = lambda x,y : x*y

print (a(4,5))

Output: 20

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2.  Here x, y, z is the input parameters, and x+y+z is the actual expression of the lambda function.

a= lambda x,y,z : x+y+z

 print (a(1,3,4))

Output: 8

Generally, We use a lambda function when we need a nameless function for a very short interval of time.

We can see the actual power of the lambda function when we have to pass a function as an argument into another function.

Let’s try to understand it with a very easy example.

def fun1(n):

  return lambda x : x * n

a = fun1(2)

print(a(12))

Output: 24

Explanation of the code:

 Here we use the def keyword for defining the normal function named fun1(n) with a single argument n. Variable a has the return value of fun1(2) which is lambda x: x * 2.

Now our code looks something like this,

a = lambda x: x*2

Which looks similar to our previous case.

Then We pass the value 12 to the lambda function as we did in our previous example.

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Conclusion :   

Python is a very powerful programming language to use it in scalable projects because it has a lot of built-in features and functions that make the life of a programmer easy.

The lambda function is one of them. We have discussed various examples in which you can use the lambda function. We hope that our guide was useful to you.

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