WHAT IS LAMBDA IN PYTHON
Tags: python, webdev, news, programming
Published: 2022-12-26 12:59:01

## INTRODUCTION

Welcome again readers and Mery Christmas to you all. Today, let discuss about lambda in python. Python is a popular, high-level programming language known for its simplicity, readability, and flexibility, it also has a lot of built in functions or tools to help programmers and one of this built in tool or function is lambda. Now let start with the practical aspect 

<img width="100%" style="width:100%" src="https://media.giphy.com/media/HivsGEo9L1TUXsINCm/giphy.gif">


## WHAT IS LAMBDA
A lambda function is small anonymous function. A lambda function can take any number of _**argument**_ , but can **only** have **one** expression. Lambda functions are used to perform operations on data, often as a part of a larger program.

**SYNTAX**

```
lambda argument : expression
```

**EXAMPLE**

```
x = lambda a : a + 10

print(x(5)) 

## output: 15 
```
In the above example lambda takes in an argument and expression, in this case a is set to be argument with an initial value set to be 5 and expression is a + 10. You might be a little confuse if you are new to python but don't worry let break it down to it smallest detail.

**BREAK DOWN**

```
Firstly we know lambda takes in an argument and expression
Now, Let: 
argument = a (and the value of a = 5 )
expression = a + 10 (but we know a is already 5, So it simply means 5 + 10 which is 15)

```
**Example Two**
Lambda functions are often used in combination with other built-in functions such as map, filter, and reduce.

```
numbers = [1, 2, 3, 4]
doubled = list(map(lambda x : x * 2, numbers))
print(doubled)  

# Output: [2, 4, 6, 8]

```

**Break Down**
From our previous example,  we know our argument here will be x and x is set to numbers ([1, 2, 3, 4]), in this case lambda map through **each** argument and multiply(*) it by the expression 2 which will give us an Output of  [2, 4, 6, 8]. 

## WHY DO YOU NEED LAMBDA FUNCTIONS? 
<img width="100%" style="width:100%" src="https://media.giphy.com/media/dILrAu24mU729pxPYN/giphy.gif">

The power of lambda is better shown when you use them as anonymous function inside another function.
Let say you have a function definition that takes one argument, and that argument will be multiplied with an unknown number. 

**Example**

```
def lamfun(n):
	return lambda a : a * n
    
doublenum = lamfun(2)

print(doublenum(10))

- 

# output: 20
```
**Break Down**
In the above example, we have a function called lamfun which takes in a argument n, now in the lamfun we have lambda **a** as the argument and **a * n** as the expression. The value is then return to the lamfun, outside the lamfun we have  doublenum = lamfun(2) which means that value of n in lumfun is 2. 

Now since we know  n = 2 we can work with our lambda function, 

- argument = a 

- expression = a * n (where n is 2 ), so a * 2 is our new expression

To get the value of **a** let look at variable doublenum in our print statement doublenum take in 10 as an argument. This value 10 is then set to be the argument for **a**. Finally we have ; 
- argument = a = 10

- expression =  10 * 2 
 which gives us an output of 20.

There you have it Home Boy, lambda in python, I hope you learnt something useful today. See you later bye.