IT 117: Intermediate Scripting

IT 117: Introduction to Scripting
Homework 5

Due
What You Need to Do
Setup On Your Machine
Specification
Functions
Test Code
Output
Suggestions
Testing on Your Machine
Copy the Script to Unix
Testing the Script on Unix (Optional)

Due

Sunday, October 5th at 11:59 PM

What You Need to Do

Create the script hw5.py
Make sure it obeys the rules in Rules for Homework Scripts
Make sure the script has a hashbang line and is executable
Move it to an an hw5 directory on pe15.cs.umb.edu

Setup On Your Machine

Open a text editor.
I would suggest the text editor built into the program IDLE.
Save the file as hw5.py
Copy the files words_1.txt and words_2.txt from /home/ghoffman/course_files/it117_files.
Use FileZilla to do this.

Specification

This script reads two text files and converts them into sets
Each file has a single word on each line
It then prints the lengths of the two sets and combinations of these sets
Then it prints the intersection of the two sets
The script must contain 3 functions
- open_file_read
- set_from_file
- print_sorted_set

Functions

open_file_read

Header
```
def open_file_read(filename):
```
It must try to create a file object for reading on the file whose name is given by the parameter filename
If it can create the object is should return it
If it cannot, it should print an error message and return None

set_from_file

Header
```
def set_from_file(file):
```
The function should loop through a text file with one word on each line
It should add all words to a set and return the set

print_sorted_set

Header
```
def print_sorted_set(s):
```
This function should print all entries in a set in sorted order

Test Code

Your script must contain the following statements
They should appear at the bottom of your script

file_1 = open_file_read("words_1.txt")
file_2 = open_file_read("words_2.txt")
if file_1 and file_2:
    set_1 = set_from_file(file_1)
    set_2 = set_from_file(file_2)
    print("set 1:", len(set_1), "elements")
    print("set 2:", len(set_2), "elements")
    print("Union sets 1 & 2:",len(set_1 | set_2), "elements")
    print("Intersection sets 1 & 2:",len(set_1 & set_2), "elements")
    print("Elements in intersection sets 1 & 2")
    print_sorted_set(set_1 & set_2)

Output

The output should look something like this

set 1: 21 elements
set 2: 27 elements
Union sets 1 & 2: 39 elements
Intersection sets 1 & 2: 9 elements
Elements in intersection sets 1 & 2
have
in
is
largely
learned
may
remote
that
the

Suggestions

Write this script in stages
Test your script at each step
Print the steps below
And check them off as you finish each one

Create the file hw5.py.
Enter the headers for open_file_read, set_from_file and print_sorted_set.
Under each header write the Python statement pass.
Run the script.
Fix any errors you find.
Copy the function open_file_read from your hw2.py.
Copy the test code into the bottom of the file.
Comment out all but the first two lines of the test code by placing the hash mark, #, at the beginning of each line.
Run the script.
You should see nothing.
Fix any errors you find.
Remove the pass statement from set_from_file.
Write a statement that defines the empty set s.
Print s.
Remove the comment from the next three lines in the test code, the lines starting with the if statement.
Run the script.
Fix any errors you find.
Remove the print statement from set_from_file.
Write a for loop that prints each line in the file.
Run the script.
Fix any errors you find.
Remove the print statement after the for loop in set_from_file.
Replace it with a statement adds the line, with the linefeed character removed, to the set s.
Outside the for loop, print the set s.
Run the script.
Fix any errors you find.
Remove the print statement from the last line of set_from_file.
Replace it with a line that returns the set s.
Remove the pass statement from print_sorted_set .
Replace it with a statement that prints the parameter s.
Uncomment the remaining lines in the test code.
Run the script.
Fix any errors you find.
Remove the print statement from print_sorted_set.
Replace it with a for loop that prints the sorted list of elements in the set.
Run the script.
Fix any errors you find.

Testing on Your Machine

Open IDLE
Use the Open command in IDLE to open hw5.py
Under the Run menu, select Run Module

Your output should look like this

set 1: 21 elements
set 2: 27 elements
Union sets 1 & 2: 39 elements
Intersection sets 1 & 2: 9 elements
Elements in intersection sets 1 & 2
have
in
is
largely
learned
may
remote
that
the

Copy the Script to Unix

Open FileZilla and connect to pe15.cs.umb.edu
Go to your it117 directory
Go to your hw directory
Right-click in the whitespace inside the hw directory
Enter hw5 in the dialog box
Click and drag your script from the bottom left panel to the bottom right panel
Right-click on the file and select "Permissions" from the menu
Enter 755 in the box provided
This will make the script executable
Click and drag words_1.txt and words_2.txtfrom the bottom left panel to the bottom right panel

Testing the Script on Unix (Optional)

Connect to pe15.cs.umb.edu using an ssh client like putty.exe (Windows) or ssh (Mac)
Go to the directory for this exercise
```
cd  it117/hw/hw5
```
Run this script
```
hw5.py
```

You should see this

set 1: 21 elements
set 2: 27 elements
Union sets 1 & 2: 39 elements
Intersection sets 1 & 2: 9 elements
Elements in intersection sets 1 & 2
have
in
is
largely
learned
may
remote
that
th