Linear Search

A simple approach is to do linear search, i.e Start from the leftmost element of list and one by one compare x with each element of list

If x matches with an element, return the index.
If x doesn’t match with any of elements, return -1.

Program:

t=input().split()
s=input()
def linearsearch(t,s):
    for i in range(len(t)):
        if t[i] ==s:
            return i
    else:
        return -1
result=linearsearch(t,s)
if result >= 0:
  print("Element found at ",result)
else:
  print("Element not found")
Input:
1 2 3 4 5
3
Output:
Element found at 2

sum of array

Binary Search

References

Allen B. Downey, “Think Python: How to Think Like a Computer Scientist‘‘, 2nd edition, Updated for Python 3, Shroff/O‘Reilly Publishers, 2016 (http://greenteapress.com/wp/thinkpython/)
Guido van Rossum and Fred L. Drake Jr, ―An Introduction to Python – Revised and updated for Python 3.2, Network Theory Ltd., 2011.
John V Guttag, ―Introduction to Computation and Programming Using Python‘‘, Revised and expanded Edition, MIT Press , 2013
Robert Sedgewick, Kevin Wayne, Robert Dondero, ―Introduction to Programming in Python: An Inter-disciplinary Approach, Pearson India Education Services Pvt. Ltd., 2016.
Timothy A. Budd, ―Exploring Python‖, Mc-Graw Hill Education (India) Private Ltd.,, 2015. 4. Kenneth A. Lambert, ―Fundamentals of Python: First Programs‖, CENGAGE Learning, 2012.
Charles Dierbach, ―Introduction to Computer Science using Python: A Computational Problem-Solving Focus, Wiley India Edition, 2013.
Paul Gries, Jennifer Campbell and Jason Montojo, ―Practical Programming: An Introduction to Computer Science using Python 3‖, Second edition, Pragmatic Programmers, LLC, 2013.