Classes and Objects 3

Today wraps up classes and objects with our continuing example of a Midshipman class, but now used properly in a separate file that we need to import. We will also look at the sklearn library introduced in the Author Detection ML lab, and discuss its classes and functions therein.

Today in Class

1. Discuss classes in multi-file programs
2. Review 'self' and __init__
3. Use sklearn as a real-world example

You should be able to understand this program.

from mids import Midshipman
      
# Create objects!
mids = list()
mids.append( Midshipman('Santa Cruz Cernik', 100) )
mids.append( Midshipman('Christie', 100) )
mids.append( Midshipman('Dollahite', 85) )
mids.append( Midshipman('Jordan', 100) )

# Do stuff!
mids[2].complain('homework')
mids[1].order_chipotle()
mids[1].chop()
mids[3].order_chipotle()
mids[0].parade()

# Print info!
for mid in mids:
    if mid.health < 90:
        print('WARNING!', end=' ')
        mid.pretty_print()
        mid.order_chipotle()

The code above only works if we have a separate file called mids.py that defines the class like so:

# mids.py
                          
class Midshipman:

    def __init__(self, name, h):
        self.name = name
        self.health = h
        self.QPR = 4.0

    def pretty_print(self):
        print(self.name, '\t', end='')
        if len(self.name) < 8:
            print('\t\thealth = ', end='')
        elif len(self.name) < 16:
            print('\thealth = ', end='')
        else:
            print('health = ', end='')
        print(self.health)
       
    def complain(self, topic):
        print(topic, 'is the worst!')
        self.health -= 5

    def order_chipotle(self):
        print(self.name, 'ordering chipotle!')
        # update some health variable
        self.health += 10

    def chop(self):
        print('Beat Army, sirs!')
        print('I love SI286!')
        self.health -= 2

    def parade(self):
        print('March march march')
        self.health -= 20