Hello everyone, welcome back to Programming In Python! 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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Code Visualization – Linear Search Algorithm
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
- Initialize a boolean variable
foundand set it to False initially - Start for loop with
iranging from 0 to the length of the list - Check if key element is equal to
L[i]- if equals
- set
foundboolean variable to `True` - print the position of the element found
- break for loop
- set
- if equals
- If the boolean variable
foundis equal toFalseafter for loop, print that the element is not found in the list
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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
if not found:
print("\n%d is not in list" % x)
Output
Know about one more search algorithm called Binary Search, you can learn about it here.