Lecture 20 — Exercises¶

Solutions to the problems below must be sent to Submitty for automatic scoring. A separate file must be submitted for each problem.

For both of these exercises download the file lec20_ex.zip from the Course Materials page on Submitty. It includes a data file and lec20_ex_start.py. You start from the latter for both exercises. You will notice that the main code in this file requests the name of a data file from the user, opens and reads the file to form a list of values, and then in a loop requests several different values to search for, outputting the result of the function call for each.

Write a Python function called linear_search() that is given two arguments: a value x and a list L. The function must return the list index of the first location of x in L. If x is not in L the function must return -1. You may use any Python list functions you wish.
What if the list is already sorted? Write a modified version of linear_search() that returns the index of the first instance of x or the index where x should be inserted if it is not in L. For example, in the list:
```
L = [1.3, 7.9, 11.2, 15.3, 18.5, 18.9, 19.7]
```
the call:
```
linear_search(11.9, L)
```
should return 3, while the call:
```
linear_search(20.5, L)
```
should return 7. You must not use binary search (even though that would be faster — this is an exercise) and you must use either a for or a while loop.