If each component is equally likely to be searched, then linear search has an average case of n+1/2 comparisons, but the average case can be affected if the search probabilities for each component vary. In computer science, a linear search or sequential search is a method for finding an component within a list.

A linear search sequentially checks each component of the list until it finds an component that matches the target value. If the algorithm reaches the end of the list, the search terminates unsuccessfully.

```
"""
This is pure Python implementation of linear search algorithm
For doctests run following command:
python -m doctest -v linear_search.py
or
python3 -m doctest -v linear_search.py
For manual testing run:
python linear_search.py
"""
def linear_search(sequence, target):
"""Pure implementation of linear search algorithm in Python
:param sequence: a collection with comparable items (as sorted items not required in Linear Search)
:param target: item value to search
:return: index of found item or None if item is not found
Examples:
>>> linear_search([0, 5, 7, 10, 15], 0)
0
>>> linear_search([0, 5, 7, 10, 15], 15)
4
>>> linear_search([0, 5, 7, 10, 15], 5)
1
>>> linear_search([0, 5, 7, 10, 15], 6)
"""
for index, item in enumerate(sequence):
if item == target:
return index
return None
if __name__ == "__main__":
user_input = input("Enter numbers separated by comma:\n").strip()
sequence = [int(item) for item in user_input.split(",")]
target_input = input("Enter a single number to be found in the list:\n")
target = int(target_input)
result = linear_search(sequence, target)
if result is not None:
print(f"{target} found at position : {result}")
else:
print("Not found")
```