# Recursively find first occurrence of a number in a list using Python

Recursion is a process where a function calls itself but with a base condition. A base condition is required in order to stop a function to call itself again.

In this tutorial, we will learn how to find the first occurrence of a number in a list recursively in Python. So, let’s get started.

### Find the first occurrence of a number in a list recursively

First, we define a function **check()** that will take a list(**n**), index(**i**) and required number(**j**) as an argument.

def check(n,i,j):

Now, we will use if-else statements.

if(i==len(n)): return "Not Found" elif(j==n[i]): return i

If index **i** is equal to the length of the list(**len(n)**), that means we have traversed the list and **j** is not found. Therefore we return a string **“Not Found”.**

Else if **j==n[i]** i.e, if number to be found and element at i^{th} index are equal. it means our number is found and returns the index **i.**

And if both the conditions are false, we return our function check() with list **n**, **j, **and next index **i+1 **so that it traverses the list from the next index.

else: return check(n,i+1,j)

This is how our code looks like.

def check(n,i,j): if(i==len(n)): return "Not Found" elif(j==n[i]): return i else: return check(n,i+1,j)

Finally, it’s time to call our function.

print("Your number found at index",check([1,2,3,2,5,6,6],0,2))

print("Your number found at index",check([1,2,3,2,5,6,6],0,4))

print("Your number found at index",check([1,2,3,2,5,6,6],0,6))

The output of our program will be like you can see below:

Your number found at index 1 Your number found at index Not Found Your number found at index 5

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