IT 117: Intermediate Scripting

IT 117: Intermediate Scripting
Homework 11

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

Due

Sunday, April 27th at 11:59 PM

What You Need to Do

Create the script hw11.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 hw11 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 hw11.py

Specification

For this script you will create two classes, Employee and ProductionWorker
ProductionWorker is a subclass of Employee

Classes

Employee

This class has two hidden attributes
- name
- number
The constructor will set both attributes
The class has 3 methods in addition to the constructor
- get_name(self)
- get_number(self)
- __str__(self)
he string returned by __str__ should return the value of all attributes

ProductionWorker

This class is a subclass of Employee
This class has two hidden attributes
- shift
- rate
The constructor must set the two hidden attributes to their default values
- shift - 1
- rate - 15.00
Since the constructor does not need values for shift and rate it will have the following header
```
def __init__(self, name, number):
```
The class has 5 methods in addition to the constructor
- get_shift(self)
- get_rate(self)
- set_shift(self, shift)
- set_rate(self, rate)
- __str__(self)
The only legal values for shift are the integers 1, 2 and 3
If set_shift gets any other value, it should print an error message
The only legal values for rate are floats from 15.00 to 50.00
If set_rate gets any other value, it should print an error message
The string returned by __str__ should return the value of all attributes

Test Code

Your script must contain the following statements

They should appear at the bottom of your script

if __name__ == '__main__':    
    e1 = Employee("Frank", 1)
    print(e1.get_name(), e1.get_number())
    print(e1)
    print()
    e2 = ProductionWorker('Sam', 2)
    print(e2.get_name(), e2.get_number(), e2.get_shift(), e2.get_rate())
    e2.set_shift('one')
    print('shift:', e2.get_shift())
    e2.set_shift(4)
    print('shift:', e2.get_shift())
    e2.set_shift(2)
    print('shift:', e2.get_shift())
    e2.set_rate('twenty')
    print('rate:', e2.get_rate())
    e2.set_rate(10)
    print('rate:', e2.get_rate())
    e2.set_rate(20)
    print('rate:', e2.get_rate())
    print(e2)

Output

The output should look something like this

Frank 1
Frank, 1

Sam 2 1 15.0
one cannot be converted into an integer
shift: 1
shift can only be 1, 2 or 3
shift: 1
shift: 2
twenty cannot be converted into a float
rate: 15.0
rate must be between 15.00 and 50.00
rate: 15.0
rate: 20.0
Sam, 2, shift: 2, rate: $20.0

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

Add a header for the class Employee to the script.
Create the method header for the constructor __init__ with parameters self, name and number.
For the body of this function, use a pass statement.
Run the script and fix any errors you find.
Copy the test code to the bottom of the script.
Comment out all the statements after
```
e1 = Employee("Frank", 1)
```
Add assignment statements for each of the attributes.
Remember the attributes must be hidden.
Run the script and fix any errors you find.
Creates the accessor methods get_name and get_number.
Uncomment the next line in the test code.
Run the script and fix any errors you find.
Create method __str__ that returns a string containing the value of all attributes with a comma between them. Remember to convert number into a string.
Remove the # from the next two lines in the test code. Run the script and fix any errors you find.
Add a header for the subclass ProductionWorker to the script.
Create the method header for the constructor __init__ with parameters self, name and number.
For the body of this function, use a pass statement.
Run the script and fix any errors you find.
You need to call the Employee constructor to set the values for name and number.
This is done with the following statement
```
Employee.__init__(self, name, number)
```
Assign shift the vale 1.
Assign rate the vale 15.00.
Uncomment the next line in the test code.
Run the script and fix any errors you find.
Creates the accessor methods get_shift and get_rate.
Uncomment the next line in the test code.
Run the script and fix any errors you find.
Create the mutator method set_shift that changes the value for shift.
This number must be an integer, so you will have to convert it.
But the conversion could fail, so you will have to do it inside a try/except statement.
Write a try/except statement.
In the try block write an assignment statement that converts the new value into an integer.
Now that the value has been converted, we must make sure its value is either 1, 2 or 3.
Write an if statement that checks whether the converted value is in the list [1,2,3].
If it is, asign this convereted value to the attribute shift.
In the else block of the if statement print an error message saying the value must be ether 1, 2 or 3.
In the except block print an error message that the value could not be converted into an integer.
Uncomment the lines down to and including
```
print('shift:', e2.get_shift())
```
Run the script and fix any errors you find.
Create the mutator method set_rate that changes the value for rate.
This number must be a float, so you will have to convert it.
Since the conversion could fail, you will have to do it inside a try/except statement.
Write a try/except statement.
In the try block write an assignment statement that converts the new value into a float.
We must check that the new value is in right range.
Write an if statement that checks whether the converted value greater than or equal to 15 and less than or equal to 50.
If it is, asign this convereted value to the attribute rate.
In the else block of the if statement print an error message saying the value must be between 15 and 50.
In the except block print an error message that the value could not be converted into a float. Uncomment the all the lines in the test code, except the last. Run the script and fix any errors you find.
Create __str__ method that returns a string containing the value of all attributes with a comma between them.
Remember to convert number, shift and rate to strings.
Remove the # from the last line in the test code.
Run the script and fix any errors you find.

Testing on Your Machine

Open IDLE
Use the Open command in IDLE to open hw11.py
Under the Run menu, select Run Module

Your output should look something like this

Frank 1
Frank, 1

Sam 2 1 15.0
one cannot be converted into an integer
shift: 1
shift can only be 1, 2 or 3
shift: 1
shift: 2
twenty cannot be converted into a float
rate: 15.0
rate must be between 15.00 and 50.00
rate: 15.0
rate: 20.0
Sam, 2, shift: 2, rate: $20.0

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 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

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/hw11
```
Run this script
```
python3 hw11.py
```

You should see something like this

Frank 1
Frank, 1

Sam 2 1 15.0
one cannot be converted into an integer
shift: 1
shift can only be 1, 2 or 3
shift: 1
shift: 2
twenty cannot be converted into a float
rate: 15.0
rate must be between 15.00 and 50.00
rate: 15.0
rate: 20.0
Sam, 2, shift: 2, rate: $20.0