Exploring Lists of Lists and File I/O in Python

CMPT 120 Lecture 31 Practice Exercises 7 Partial Solution

Goals for Today! 1. Exploring Lists of Lists -> good prep for our Assignment 2 2. Exploring File I/O -> also good prep for our Assignment 2 3. Practising Selection and Insertion Sort 2

Question 1 Exploring Lists of Lists 1. Have a look at this code https://repl.it/repls/FuzzyGlitteringTexts What does it do? Add code to it to 2. Create a few more floor patterns 3. Put the string 'MM' at the centre of the first floor pattern Hint: Put the string in the list of lists variable aFloor 4. Printing: how differently would these three Python code fragments print the content of the list of lists aFloor 1) print(aFloor) 2) for row in range(theHeight): print(aFloor[row]) 3) the function def printFloor(theFloor, theHeight): Solution: https://repl.it/repls/MoralJitteryMatter 3

Question 1 Exploring Lists of Lists (cont d) Imagine you are an interior decorator and would like to see what the floor plan would look like if you were to place a sofa on the east edge of the room 5. Create a function that places a sofa (2 cells deep by 6 cells long), i.e., the string 'SS' along the right- hand side edge of the floor Remember: The cells are 2-character wide and 1-character high no solution yet 4

Question 2 Exploring File I/O a) Have a look at the 5 demos in this code https://repl.it/repls/IllSomePasswords What do they do? no solution yet b) Problem Statement: Write a Python program that reads the file words.txt found here: http://greenteapress.com/thinkpython2/code/words.txt and prints only the words it contains that have more than 20 characters (not counting whitespace and newline character) Our Python program must print one word per line. 5

Question 3 a) Selection Sort Visualize the execution of the Selection Sort using https://visualgo.net/en/sorting Once you have a good idea how Selection Sort works, sort the following data: 3,38,5,47,15,36,26,27,2,4,19 using Selection Sort and write down what the unsorted section of the data looks like once 3 iterations of Selection Sort have executed, in order words, once data has 2,3,4 in its sorted section: 2,3,4,__ 47,15,36,26,27,38,5,19__ 6

Question 3 b) Insertion Sort Visualize the execution of the Insertion Sort using https://visualgo.net/en/sorting Once you have a good idea how Insertion Sort works, sort the following data: 3,38,5,47,15,36,26,27,2,4,19 using Insertion Sort After 3 iterations of Insertion Sort, does the unsorted section of data look the same as in your answer to Question 3 a)? No Does the sorted section of data look the same? No 7