While Loops

For this challenge question, you’re going to practice using a while loop to iterate over a string!

Start by creating a file in your CQs folder called cq03_while_loops.py. Initialize with a docstring and an __author__ variable.

num_instances

For this assignment, you’re going to write a function called num_instances. Given two strings, phrase and search_char (a single character), num_instances should return the count of occurrences of search_char in phrase.

Here’s an example of what it should look like when tested in your REPL:

/workspace (main*) > python
>>> from CQs.cq03_while_loops import num_instances
>>> num_instances(phrase="HelloHeLloHEllo", search_char="e")
2
>>> num_instances(phrase="HelloHelloHello", search_char="e")
3
>>> num_instances(phrase="Happy Tuesday!", search_char="y")
2
>>> num_instances(phrase="Happy Tuesday!", search_char="z")
0

Note that num_instances is case-sensitive, so "e" doesn’t equal "E".

Guide

If you don’t know where to start, try following these steps:

• Start by writing the signature of the function.
• Create a local variable called count with the initial value of 0. This variable can be increased every time you find an instance of search_char in phrase.
• Next create another local variable that will track your index so you can loop over every element of phrase.
• Now, use a while loop to loop over every element of phrase and count the number of times search_char appears!

Submission

Create a .zip file by running the following command in your terminal:

python -m tools.submission CQs/cq03_while_loops.py

Then, drag and drop that .zip file into Gradescope!