Python Classes are all types –
print( ' The type of 1 is: ', type(1))
print ( ' The type of [] is:', type([]))
A_class = type('A class' , () , {} )
print('The type of A_class is :' , type(A_class))
an_inst = A_class()
print('The type of an_inst is: ' , type(an_inst)) class Basic():
start = 1
def a_method(self) :
return 'This is an instance of ' + str (self.__class__)
basic_inst = Basic()
print('The type of Basic is:' , type(Basic))
print('The type of basic_inst is:',type(basic_inst))
print('Calling a_method returns:',basic_inst.a_method()) Class Definitions
''' Demonstrate class defnitions '''
class Base_Model():
'''Represent the base model of a car '''
trim = 'normal'
engine_liters = 1.5
def engine_sound(self):
return 'putt, putt'
def horn_sound(self):
return 'beep, beep'
def __str__(self):
return 'Base Model' coop = Base_Model()
print('%s has %s trim level.' % (coop, coop.trim))
print('%s has a %s liter engine.' % (coop, coop.engine_liters))
print('%s engine sounds like %s.' % (coop, coop.engine_sound()))
print('%s horn sounds like %s.' % (coop, coop.horn_sound())) Class Initialization
''' Demonstrate class initialization '''
import locale
import sys class Base_Model() :
''' Represent the base model of a car '''
trim = 'normal'
engine_liters = 1.5 def __init__(self, price, transmission='automatic', color='white'):
self.price = price
self.transmission = transmission
self.color = color def info(self):
if sys.platform.startswith('win'):
locale.setlocale(locale.LC_ALL, 'us')
else:
locale.setlocale(locale.LC_ALL, 'en_US.utf8')
print('The price of %s was %s.' % (self, locale.currency(self.price))) def __str__(self):
return 'a %s base model with %s transmission' % (self.color, self.transmission)
coop = Base_Model(25000)
coop.info()
coop_blue = Base_Model(price=25500,color='blue')
coop_blue.info() coop_manual_red = Base_Model(26000, 'manual', 'red')
coop_manual_red.info() coop_manual_green = Base_Model(color='green' , transmission='manual', price=26300)
coop_manual_green.info() Class Methods
''' Demonstrate class methods '''
import locale
import sys class Base_Model():
''' Represent the base model of a car '''
trim = 'normal'
engine_liters = 1.5
miles_range = 450
tank_capacity = 45
color = 'white'
transmission = 'automatic' @classmethod
def miles_per_liter(cls) :
return cls.miles_range / cls.tank_capacity @classmethod
def miles_per_gallon(cls) :
return cls.miles_per_liter() * 3.78541
def __init__(self, price, transmission='automatic' , color='white' ):
self.price = price
self.transmission = transmission
self.color = color def info(self):
if sys.platform.startswith('win'):
locale.setlocale(locale.LC_ALL , 'us')
else:
locale.setlocale(locale.LC_ALL , 'en_US.utf8 ')
print('The price of %s was %s. ' %(self, locale.currency(self.price))) def __str__(self):
return 'a %s base model with %s transmission' %(self.color, self.transmission) coop = Base_Model(color='green' , transmission='automatic', price=25000)
coop.info()
print('The %s gets %4.1f miles per gallon' % (coop, coop.miles_per_gallon()))
print('The %s gets %4.1f miles per gallon' % (Base_Model , Base_Model.miles_per_gallon())) class Sport_Model(Base_Model) :
''' Represent the sport model of a car based on a base mode '''
engine_liters = 2.0
miles_range = 400 coop_sport = Sport_Model(color='green' , transmission='manual', price=26300)
coop_sport.info()
print('The %s gets %4.1f miles per gallon' % (coop_sport, coop_sport.miles_per_gallon()))
print('The %s gets %4.1f miles per gallon' % (Sport_Model , Sport_Model.miles_per_gallon())) 