• 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

Thursday, October 23rd at 11:59 PM

What You Need to Do

• Create the script hw10.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 hw10 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 hw10.py
• Using FileZilla, copy the file temps.txt from /home/ghoffman/course_files/it116_files to the directory on your machine that holds hw10.py
  

Specification

• This script will read a file that records temperature for different dates
• The data in the file looks like this

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

• The script calculates the average, maximum and minimum temperatures from this file using lists
• The script must contain 3 functions
  • temp_list_from_file
  • mean_temp
  • max_min_temp

Functions

temp_list_from_file

• Header

   def temp_list_from_file(file):

• This function will read in a file containing values for date and temperature on each line and return a list of temperatures

mean_temp

• Header

  def mean_temp(list):

• The function has one parameter, list, a list of temperatures
• The function must read in the list with a for loop to get the temperature for each date
• It must turn the temperature value into an integer and use it to calculate the mean, or average temperature
• It must return the average temperature, rounded to an integer
• The function should use the following algorithm

	set count to 0
	set total to 0
	for each temp in the list:
	   increment count
	   turn temp into an integer
	   add temp to total
	find the mean by dividing total by count
	return the mean using round to turn it into an integer

max_min_temp

• Header

  def max_min_temp(list):

• The function must read in the list with a for loop to get the temperature for each date
• It must turn the temperature value into an integer and use it to calculate the minimum and maximum temperatures
• The function should use the following algorithm

	set max to 0
	set min to 500
	for each temp in the list:
	   turn temp into an integer
	   if temp is greater than max:
	      set max to temp
	   if temp is less than min:
	      set min to temp
	return max and min

Test Code

• Your script must contain the following statements

  FILENAME  = "temps.txt"
  file      = open(FILENAME, "r")
  temp_list = temp_list_from_file(file)
  mean = mean_temp(temp_list)
  print(mean)
  max_min_temp(temp_list)
  max_temp, min_temp = max_min_temp(temp_list)
  print(max_temp, min_temp)

• They should appear at the bottom of your script

Output

• The output should look something like this

  77
  89 66

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

1. Create a hashbang line on the first line of the script.
   Copy only the function headers for the three 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.
2. Remove the pass statement from temp_list_from_file.
   Replace it with a statement that creates the empty list list.
   Write a for loop that prints every line in the file.
   Add the text code to the bottom of the script. Comment out all but the first three lines of the test code. Run the script.
   Fix any errors you find.
3. Remove the print statement.
   Replace it with a statement that uses split on the line to assign values to the variables date and temp.
   Print temp.
   Run the script.
   Fix any errors you find.
4. Remove the print statement.
   Replace it with a statement that appends temp to list.
   Outside the for loop print list.
   Run the script.
   Fix any errors you find.
5. Remove the print statement.
   Replace it with a statement that returns list.
   Remove the pass statement from mean_temp.
   Replace it with a statement that sets total to 0.
   Print the parameter list.
   Uncomment the next line in the test code.
   Run the script.
   Fix any errors you find.
6. Remove the print statement.
   Replace it with a for loop over list using temp as the loop variable.
   Inside the loop print temp.
   Run the script.
   Fix any errors you find.
7. Remove the print statement.
   Replace it with an assignment statement that turns temp into an integer using int().
   Add temp to total.
   Outside the for loop print total.
   Run the script.
   Fix any errors you find.
8. Remove the print statement.
   Replace it with a statement that sets average to total divided by the length of list. Print average.
   Run the script.
   Fix any errors you find.
9. Remove the print statement.
   Replace it with a return statement that returns average turned into an integer using round.
   Uncomment the next line in the test code.
   Run the script.
   Fix any errors you find.
10. Remove the pass statement from max_min_temp.
    Set max to 0.
    Set min to 500.
    Print max and max.
    Uncomment the next line in the test code.
    Run the script.
    Fix any errors you find.
11. Remove the print statement.
    Replace it with a for loop that runs over list using the loop variable temp.
    Inside the loop print temp.
    Run the script.
    Fix any errors you find.
12. Remove the print statement.
    Replace it with a statement that converts temp to an integer using int().
    Write an if statement that will run if temp is greater than max.
    Inside the if statement set max to temp.
    Print max.
    Run the script.
    Fix any errors you find.
13. Remove the print statement.
    Write an if statement that will run if temp is less than min.
    This statement must be outside the first if statement but inside the for loop.
    Inside this newest if statement print set min to temp.
    Print min.
    Run the script.
    Fix any errors you find.
14. Remove the print statement.
    Outside the for loop return max and min.
    Uncomment the last lines in 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 hw10.py
• Run your script inside IDLE
• Your output should look something like this

  77
  89 66

• 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 hw10 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 temps.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/hw10

• Run this script

  ./hw10.py

• You should see something like this

   77
  89 66

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