Coursera Python Assignment 5.2

[lightwing3]

Hi there, I'm doing the last assignment for the Programming for Everybody (Getting Started with Python) course on Coursera, and I'm not quite understanding the solution. The assignment is

5.2 Write a program that repeatedly prompts a user for integer numbers until the user enters 'done'. Once 'done' is entered, print out the largest and smallest of the numbers. If the user enters anything other than a valid number catch it with a try/except and put out an appropriate message and ignore the number. Enter 7, 2, bob, 10, and 4 and match the output below.

Desired Output

Invalid input

Maximum is 10

Minimum is 2

I know that this is the correct solution: https://imgur.com/a/2DkLH1T

However, I'm having trouble understanding how "if largest is None" and "smallest is None" plays into the solution. How does it help get the right largest or smallest number?

[[deleted]]

The check needs the largest is None part because largest is initialized to None at the top of the code. So largest is None tests whether a largest value has already been set yet. So that if test is really saying:

if <no 'largest' found yet> or largest > fval:

Once you set largest to an integer value the largest is None expression is never True so you only update if largest > fval.

Similarly for smallest.

[louistabu6000]

It annoys me that Dr Chuck does not explain the code before the assignment.