IT 116: Introduction to Scripting

IT 116: Introduction to Scripting
Homework 9

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, April 13th at 11:59 PM

What You Need to Do

Create the script hw9.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 hw9 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 hw9.py
Using FileZilla, copy the file rainfall.txt from /home/ghoffman/course_files/it116_files.

Specification

This script will read a file that records rainfall for different dates
Each line in the file has a date and the rainfall on that date

The data in the file looks like this

2020-11-01	0
2020-11-02	1
2020-11-03	0
...

The script will calculate the average rainfall
Along with the highest rainfall and the date on which it occurred
The script must contain 2 functions
- average_rain
- max_rain_date

Functions

average_rain

Header
```
def average_rain(file):
```
The function has one parameter, file, a file object
The function must read in the file with a for loop to get the rain for each date
Add up all the rain values and divide by the number of entries to calculate the average
It must return the average rainfall, rounded to 2 decimal points

max_rain_date

Header
```
def max_rain_date(file):
```
The function has one parameter, file, a file object
The function must read in the file with a for loop and get the date and rainfall from each line
It must find the maximum rainfall and the date on which it occurred
And return these two values

Test Code

Your script must contain the following statements

FILENAME = "rainfall.txt"
file = open(FILENAME, "r")
average = average_rain(file)
print(average)
file.close()
file = open(FILENAME, "r")
max_rain_date(file)
file = open(FILENAME, "r")
max_rain, max_date = max_rain_date(file)
print(max_rain, max_date)

They should appear at the bottom of your script

Output

The output should look something like this
```
1.23
6 2020-11-07
```

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 a hashbang line on the first line of the script.
Copy only the function headers for the two functions listed above into your script file.
Under each header, write pass.
Make sure this statement is indented.
Run the script.
Fix any errors you find.
Remove the pass from average_rain.
Create the variables count and total giving them initial values of 0.
Print count and total.
Copy all of the test code to the bottom of your script.
Comment out all but the first three lines of the test code.
Do this by inserting # at the beginning of the line.
This will keep some lines of the test code from running at this time.
Run the script.
Fix any errors you find.
Remove the print statement from average_rain.
In it's place write a for loop that prints every line in the file.
Run the script.
Fix any errors you find.
Remove the print statement.
Replace it with a statement that uses split on the line to assign values to the variables date and rain.
Print date and rain.
Run the script.
Fix any errors you find.
Remove the print statement.
Replace it with a statement that turns rain into an integer.
Next increment count.
Add a statement that adds rain to total.
Outside the for loop, print count and total.
Run the script.
Fix any errors you find.
Remove the print statement.
Replace it with a statement that calculates the average and assigns it to the variable average.
Next write an assignment statement that rounds average to 2 decimal places.
When round is run with two arguments, the second argument specifies that number of decimal places.
Return average.
Uncomment the first commented line in the test code.
Run the script.
Fix any errors you find.
Remove the pass statement from max_rain_date.
Define the variable max_rain and set it to 0.
Define the variable max_date and set it to the empty string.
Print the value of both variables.
Uncomment the next 3 lines in the test code.
Run the script.
Fix any errors you find.
Remove the print statement.
Replace it with a for loop that prints every line in the file.
Run the script.
Fix any errors you find.
Remove the print statement.
Replace it with a statement that uses split to assign values to the variables date and rain.
Print date and rain.
Run the script.
Fix any errors you find.
Remove the print statement.
Replace it with a statement that turns rain into an integer.
Below this write an if statement that will run in the value of rain is greater than max_rain.
Inside the if statement print the value of rain.
Run the script.
Fix any errors you find.
Remove the print statement.
Replace it with a statement that sets max_rain to the value of rain.
Next write a statement that sets max_date to date.
Print max_rain and max_date.
Run the script.
Fix any errors you find.
Remove the print statement.
Outside the for loop return both max_rain and max_date.
Uncomment the remaining lines in the test script. Run the script.
Fix any errors you find.

Testing on Your Machine

Open IDLE
Use the Open command in IDLE to open hw9.py
Run your script inside IDLE
Your output should look something like this
```
1.23
6 2020-11-07
```
The text in blue is what you enter at the command line

Copy the Script to Unix

Open FileZilla and connect to pe15.cs.umb.edu
Go to your it116 directory
Go to your hw directory
Right-click in the whitespace inside the hw directory
Enter hw9 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 rainfall.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  it116/hw/hw9
```
Run this script
```
./hw9.py
```
You should see something like this
```
1.23
6 2020-11-07
```
The text in blue is what you enter at the command line