IT 117: Intermediate Scripting

IT 117: Intermediate to Scripting
Homework 4

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, February 22nd at 11:59 PM

What You Need to Do

Create the script hw4.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 hw4 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 hw4.py
Copy the file quiz_scores.txt from /home/ghoffman/course_files/it117_files.
Use FileZilla to do this.

Specification

This script must read in a file containing a list of students and their scores on quizzes

The file has entries like the following

04352948 77 84 51 71 72 92 85 51 75 66 
03981869 76 73 94 53 59 62 86 50 70 52 
03201438 68 50 71 71 83 95 64 62 83 96
...

The first value on each line is a student ID and the rest are quiz scores
The script must create two dictionaries and print them
The keys for both dictionaries are student IDs
The values of the first dictionary must be an list of integer scores for each student
The values of the second dictionary must be the rounded average of quiz scores for each student
These averages should be integers
The script must contain 4 functions
- open_file_read
- quiz_dictionary_create
- average_dictionary_create
- print_dictionary

Functions

open_file_read

Header
```
def open_file_read(filename):
```
This script tries to create a file object for reading
The name of the file is given by the parameter filename
If the script can create the object it should return it
If it is cannot create the object it should print an error message and return None

quiz_dictionary_create

Header
```
def quiz_dictionary_create(file):
```
The parameter file is a file object on the text file mentioned above
The script must loop through this file creating entries in a dictionary
The keys of the dictionary are student IDs
And the values are lists of the quiz scores
The quiz scores must be stores as integers
The function then returns this dictionary
The function should use the following algorithm

	create an empty dictionary
	for each line in the file
		run split on the line to create the list fields
		remove the first element of fields and save it as the student ID
		create an empty list scores
		for each element in fields
			convert the element into an integer
			add this integer to scores
	return the dictionary

average_dictionary_create

Header
```
def average_dictionary_create(dict):
```
The parameter dict is the dictionary created above
This function creates a new dictionary
The ID is the key for this new directory
The value is the rounded average of the scores
The function returns this dictionary
The function should use the following algorithm

	for each entry in the dictionary
		store the key
		get the list of scores
		set total to 0
		for each score in the list of scores
			add score to total
		get the average by dividing total by the number of scores
		create a dictionary entry with this ID and the average
	return the dictionary

print_dictionary

Header
```
def print_dictionary(dict):
```
This function prints the key and value for every entry in the dictionary sorted by key

Test Code

Your script must contain the following statements

file   = open_file_read("quiz_scores.txt")
scores = quiz_dictionary_create(file)
print_dictionary(scores)
print()
averages = average_dictionary_create(scores)
print_dictionary(averages)

They should appear at the bottom of your script
This code will only work if you have copied quiz_scores.txt into the same directory as your script
You will find this file in /home/ghoffman/course_files/it117_files

Output

The output should look something like this

01583835 [57, 69, 66, 88, 69, 77, 80, 79, 53, 57]
03201438 [68, 50, 71, 71, 83, 95, 64, 62, 83, 96]
03981869 [76, 73, 94, 53, 59, 62, 86, 50, 70, 52]
04352948 [77, 84, 51, 71, 72, 92, 85, 51, 75, 66]
07787151 [81, 78, 61, 89, 74, 73, 87, 77, 92, 52]

01583835 70
03201438 74
03981869 68
04352948 72
07787151 76

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 hw4.py.
Enter the headers for each of the required functions.
Under each header write the Python statement pass.
Run the script.
Fix any errors you find.
Replace the pass statement in open_file_read with the body of the code from your hw3.py script.
Copy the test code to the bottom of the file.
Comment out all but the first line in the file.
Run the script entering both a real filename and the name of a file that does not exists.
Fix any errors you find.
Remove the pass statement from quiz_dictionary_create.
Replace it with a statement that creates an empty dictionary named quiz_scores.
Write a for loop that loops through the file using the file object file.
Inside the for loop write a print statement to print the line.
Uncomment the second line of the test code.
Run the script.
You should see something like this
```
04352948 77 84 51 71 72 92 85 51 75 66 

03981869 76 73 94 53 59 62 86 50 70 52 

03201438 68 50 71 71 83 95 64 62 83 96 

01583835 57 69 66 88 69 77 80 79 53 57 

07787151 81 78 61 89 74 73 87 77 92 52 
```
Fix any errors you find.

Remove the print statement.
Run split on the line and store it in the variable fields.
Print fields.
Run the script.
You should see

['04352948', '77', '84', '51', '71', '72', '92', '85', '51', '75', '66']
['03981869', '76', '73', '94', '53', '59', '62', '86', '50', '70', '52']
['03201438', '68', '50', '71', '71', '83', '95', '64', '62', '83', '96']
['01583835', '57', '69', '66', '88', '69', '77', '80', '79', '53', '57']
['07787151', '81', '78', '61', '89', '74', '73', '87', '77', '92', '52']

Fix any errors you find.

Remove the print statement.
Set the variable id to the first element fields.
Do this by calling the list method pop with an argument of 0.
This will also remove the first element from fields.
Print id.
Run the script.
You should see
```
04352948
03981869
03201438
01583835
07787151
```
Fix any errors you find.
Remove the print statement.
Create the empty list scores.
Write a for loop that loops over the remaining elements of fields.
Inside the for loop print each score.
You should see
```
77
84
51
71
...
```
Run the script.
Fix any errors you find.
Remove the print statement.
Replace it with a statement that adds the element to scores after converting it to an integer.
Outside the inner for loop print scores.
Run the script.
You should see
```
[77, 84, 51, 71, 72, 92, 85, 51, 75, 66]
[76, 73, 94, 53, 59, 62, 86, 50, 70, 52]
[68, 50, 71, 71, 83, 95, 64, 62, 83, 96]
[57, 69, 66, 88, 69, 77, 80, 79, 53, 57]
[81, 78, 61, 89, 74, 73, 87, 77, 92, 52]
```
Fix any errors you find.
Replace the print statement with a line that adds an entry to the dictionary quiz_scores.
id will be the key and scores will be the value.
After the outer for loop print quiz_scores.
Run the script.
You should see something like this
```
{'04352948': [77, 84, 51, 71, 72, 92, 85, 51, 75, 66], '03981869': [76, 73, 94, 53, 59, 62, 86, 50, 70, 52], ... 
```
Fix any errors you find.
Remove the print statement.
Replace it with a statement that returns quiz_scores.
Remove the pass statement from print_dictionary.
Replace it with the body of the code from print_dictionary in hw3.py.
Uncomment the third line of the test code.
Run the script.
You should see
```
01583835 [57, 69, 66, 88, 69, 77, 80, 79, 53, 57]
03201438 [68, 50, 71, 71, 83, 95, 64, 62, 83, 96]
03981869 [76, 73, 94, 53, 59, 62, 86, 50, 70, 52]
04352948 [77, 84, 51, 71, 72, 92, 85, 51, 75, 66]
07787151 [81, 78, 61, 89, 74, 73, 87, 77, 92, 52]
```
Fix any errors you find.

Remove the pass statement from average_dictionary_create.
Replace it with a statement that creates an empty dictionary.
Write a for loop that loops through the dictionary pointed to by the parameter dict.
Use id as the loop variable.
Inside the loop create the variable scores and set it equal to the value associated with id.
Print scores.
Uncomment the next two lines from the test code.
Run the script.
You should see

01583835 [57, 69, 66, 88, 69, 77, 80, 79, 53, 57]
03201438 [68, 50, 71, 71, 83, 95, 64, 62, 83, 96]
03981869 [76, 73, 94, 53, 59, 62, 86, 50, 70, 52]
04352948 [77, 84, 51, 71, 72, 92, 85, 51, 75, 66]
07787151 [81, 78, 61, 89, 74, 73, 87, 77, 92, 52]

[77, 84, 51, 71, 72, 92, 85, 51, 75, 66]
[76, 73, 94, 53, 59, 62, 86, 50, 70, 52]
[68, 50, 71, 71, 83, 95, 64, 62, 83, 96]
[57, 69, 66, 88, 69, 77, 80, 79, 53, 57]
[81, 78, 61, 89, 74, 73, 87, 77, 92, 52]

Fix any errors you find.

Remove the print statement.
Create the variable total and set it to 0.
Use a for loop to iterate through the values in scores.
Inside the loop add each element to total.
After the loop print total.
Run the script.
You should see

01583835 [57, 69, 66, 88, 69, 77, 80, 79, 53, 57]
03201438 [68, 50, 71, 71, 83, 95, 64, 62, 83, 96]
03981869 [76, 73, 94, 53, 59, 62, 86, 50, 70, 52]
04352948 [77, 84, 51, 71, 72, 92, 85, 51, 75, 66]
07787151 [81, 78, 61, 89, 74, 73, 87, 77, 92, 52]

724
675
743
695
764

Fix any errors you find.

Remove the print statement.
Calculate the average grade and set it equal to the variable average.
The average is total divided by the length of the list scores.
Turn this value into an integer using round.
Create an entry in the dictionary where id is the key and average is the value.
After the outer loop, print the dictionary.
Run the script.
You should see
```
01583835 [57, 69, 66, 88, 69, 77, 80, 79, 53, 57]
03201438 [68, 50, 71, 71, 83, 95, 64, 62, 83, 96]
03981869 [76, 73, 94, 53, 59, 62, 86, 50, 70, 52]
04352948 [77, 84, 51, 71, 72, 92, 85, 51, 75, 66]
07787151 [81, 78, 61, 89, 74, 73, 87, 77, 92, 52]

{'04352948': 72, '03981869': 68, '03201438': 74, '01583835': 70, '07787151': 76}
```
Fix any errors you find.
Remove the print statement.
Replace it with a statement that returns the dictionary.
Uncomment the last line of the test code.
Run the script.
Fix any errors you find.

Testing on Your Machine

Open IDLE
Use the Open command in IDLE to open hw4.py
Under the Run menu, select Run Module

Your output should look something like this

01583835 [57, 69, 66, 88, 69, 77, 80, 79, 53, 57]
03201438 [68, 50, 71, 71, 83, 95, 64, 62, 83, 96]
03981869 [76, 73, 94, 53, 59, 62, 86, 50, 70, 52]
04352948 [77, 84, 51, 71, 72, 92, 85, 51, 75, 66]
07787151 [81, 78, 61, 89, 74, 73, 87, 77, 92, 52]

01583835 70
03201438 74
03981869 68
04352948 72
07787151 76

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 hw4 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 quiz_scores.txt from 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/hw4
```
Run this script
```
hw4.py
```

You should see something like this

01583835 [57, 69, 66, 88, 69, 77, 80, 79, 53, 57]
03201438 [68, 50, 71, 71, 83, 95, 64, 62, 83, 96]
03981869 [76, 73, 94, 53, 59, 62, 86, 50, 70, 52]
04352948 [77, 84, 51, 71, 72, 92, 85, 51, 75, 66]
07787151 [81, 78, 61, 89, 74, 73, 87, 77, 92, 52]

01583835 70
03201438 74
03981869 68
04352948 72
07787151 76