Python program to implement Linear Search Algorithm

Hello everyone, welcome back to programminginpython.com! Here I am going to explain to you how to implement a linear search algorithm in python. This linear search is a basic search algorithm that searches all the elements in the list and finds the required value. This is also known as a sequential search.

Here in this technique, I compare each and every element with the key element to be found, if both of them match, the algorithm returns that element is found and its position.

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Time Complexity

 Best Case O(1) Average Case O(n) Worst Case O(n)

Algorithm

Given a list L of `n` elements with values or records,L0 ... Ln-1 and key/target element K, linear search is used to find the index/position of the target K in list L

1. Initialize a boolean variable found and set it to False initially
2. Start for loop with i ranging from 0 to the length of the list
3. Check if key element is equal to L[i]
1. if equals
1. set found boolean variable to `True`
2. print the position of the element found
3. break for loop
4. If the boolean variable found is equal to False after for loop, print that the element is not found in the list

Program

__author__ = 'Avinash'

lst = []
num = int(input("Enter size of list: \t"))
for n in range(num):
numbers = int(input("Enter any number: \t"))
lst.append(numbers)

x = int(input("\nEnter number to search: \t"))

found = False

for i in range(len(lst)):
if lst[i] == x:
found = True
print("\n%d found at position %d" % (x, i))
break