IT 116: Introduction to Scripting
Homework 11

Deliverables

There is one deliverable for this assignment: It must be in an hw11 directory, which you must create inside a hw directory inside you it116 directory.

Make sure the script obeys all the rules in the Script Requirements page.

Copy the file numbs.txt, which you will find in /home/ghoffman/course_files/it116_files into your hw11 directory . 
cp  /home/ghoffman/course_files/it116_files/numbs.txt  .

Specification

The script must define 4 functions You must not use any external Python module in the statistical calculations needed for these functions.

read_file_into_integer_list

This functions must have the following header 
    def read_file_into_integer_list(filename):
This function must read in the numbers contained in a file, convert them to integers and add them to an array.
The function must return the array of integers it creates.
If the function cannot open the file, it should return an empty list.

list_mean

This functions must have the following header 
    def list_mean(list):
This function must calculate the average (mean) of the integers in a list.
It must return the the rounded average.

list_median

This functions must have the following header 
    def list_median(list):
This function must sort a list and return the value of the element in the middle of sorted the list.
You may assume that the list has an odd number of elements.

list_range

This functions must have the following header 
    def list_range(list):
This function must return the difference between the highest and lowest number in a list.

Suggestions

  1. Create the script file and make it executable.
    Run the script.
    It should produce no output. Fix any errors you find.
  2. Create a function header for each of the four functions.
    For the body of each function write pass.
    Copy the test code below to the bottom of your script.
    Run the script.
    All the values should be None.
    Fix any errors you find.
  3. Remove the pass statement from read_file_into_integer_list.
    Add a statement that creates an empty list and assigns it to the variable list.
    Within a try/except statement, create a file object on the file whose name is given as a parameter to this function.
    The except code block should return list. Run the script and fix any errors you find.
  4. Add an else clause to the try/except statement.
    Inside this clause add a for loop that reads each line in the file and prints it.
    Run the script and fix any errors you find.
  5. Change the body of the for loop so it converts each line of the file into an integer and adds it to list.
    Outside the for loop, return list.
    Run the script and fix any errors you find.
  6. Remove the pass statement from list_mean.
    Create the variable total and set it to 0.
    Write a for loop on the file given as a parameter which prints each number in the list.
    Run the script and fix any errors you find.
  7. Replace the print statement in the for loop with a statement that adds the value of the number to total.
    Outside the for loop, return the rounded value of total divided by the length of the list.
    Run the script and fix any errors you find.
  8. Remove the pass statement from list_median.
    Sort the list.
    Create the variable index and assign it the value of the length of the list divided by 2 using integer division.
    Return the value of the list element that has this index.
    Run the script and fix any errors you find.
  9. Remove the pass statement from list_range.
    Sort the list.
    Return the difference between the last and first elements of the list.
    Run the script and fix any errors you find.

Test Code

At the bottom of the script you must have the following code 
numbers = read_file_into_integer_list("xxxxxxx")
numbers = read_file_into_integer_list("numbs.txt")
print("numbers:             ", numbers)
print("list_mean(numbers):  ", list_mean(numbers))
print("list_median(numbers):", list_median(numbers))
print("list_range(numbers): ", list_range(numbers))

Testing

Your output should look like this 
numbers:              [46, 19, 35, 43, 35, 33, 42, 6, 25, 6, 19, 17, 31, 1, 23, 14, 18, 24, 24]
list_mean(numbers):   24
list_median(numbers): 24
list_range(numbers):  45
Be sure to run this script on the Unix machine so you know it works in the environment in which I will run it when I score your homework.