# Linear Search in Python

Harshit Jindal Oct 10, 2023
Note
If you want to understand Linear Search in detail then refer to the Linear Search Algorithm article.

## Linear Search Algorithm

Let us assume that we have an unsorted array `A[]` containing `n` elements, and we want to find an element - `X`.

• ##### Traverse all elements inside the array starting from the leftmost element using a `for` loop and do the following:
• If the value of `A[i]` matches with `X`, then return the index `i`. (If there can be multiple elements matching `X`, then instead of returning the index `i`, either print all indexes or store all the indexes in an array and return that array.)
• Else move on to the next element.
• If it is at the last element of the array, quit the `for` loop.

## Linear Search Python Implementation

``````def linearsearch(arr, n, x):

for i in range(0, n):
if arr[i] == x:
return i
return -1

arr = [1, 2, 3, 4, 5]
x = 1
n = len(arr)
position = linearsearch(arr, n, x)
if position == -1:
else:
print("Element is present at index", position)
``````

Output:

``````Element is found at index: 1
``````

The time complexity of the above algorithm is `O(n)`.

Harshit Jindal has done his Bachelors in Computer Science Engineering(2021) from DTU. He has always been a problem solver and now turned that into his profession. Currently working at M365 Cloud Security team(Torus) on Cloud Security Services and Datacenter Buildout Automation.