Quiz #5 for October 13, 2020

Please use your Python system (IDLE or something else) to compute the following. Be prepared to show your work!

1. If you want to write a program that prints integers from 1 to 19 by twos, which of the following is the most appropriate to use?
   1. A for loop using range(1, 19, 2)
   2. A for loop using range(1, 20, 2)
   3. A for loop using range(1, 20) and a continue statement to prevent the even numbers from printing
   4. A while loop that counts from 1 to 19 by twos, printing the numbers

   Answer: (a) does not include 19, as range() goes up to but not including the upper number. (c) will work, but is clumsy and has an unnecessary if statement. (d) works, but uses a construct (while) intended for an indefinite loop, not a definite one. So (b) is the best answer.

2. You want to use a while statement to loop, reading input lines until someone types quit. Which of the following is the best way to do this?

   1. A for loop using True as the iterator, and an if statement that compares the input to "quit" and if they match, executes a break
   2. A while loop with input() to read input, and a condition that compares the input to the string "quit"
   3. A while loop with input() to read input, and an if statement that compares the input to "quit" and if they match, executes a break
   4. A while loop with input() to read input, and an if statement that compares the input to "quit" and if they match, executes a continue

   Answer: (a) is obviously wrong, as it doesn’t use a for loop. (d) is wrong, as the continue causes the loop to be executed again, starting at the beginning of the loop. Both (b) and (c) are correct; which on e you should use depends on whether you will use the input in the loop and not just in the conditional. If you will use the input elsewhere in the loop, then (c) is better; if it will only be used in the conditional, (b) would be more appropriate.

Matt Bishop Office: 2209 Watershed Sciences Phone: +1 (530) 752-8060 Email: mabishop@ucdavis.edu

MHI 289I, Programming for Health Informatics Version of October 14, 2020 at 11:53PM

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