'''This code is from a free lesson by Majid Khorashadizadeh: deep dive in OOP You can follow his youtube channel''' #comparison of objects of classes ''' Assume that we have two numbers and we want to compare them. We can do this in two ways: a = 10 b = 20 print(a>b) print(a.__lt__(b)) ''' class Student(): def __init__ (self, name, age): self.name = name self.age = age self.courses = dict() def add_course(self, cname, cgrade): self.courses[cname] = cgrade def __str__(self): txt = f'{self.name}\n{self.courses}' return txt #for calculating avg def get_avg(self): avg = sum(self.courses.values())/len(self.courses) return avg #__lt__ means lower than < def __lt__(self, other): if isinstance (other, Student): if self.get_avg() < other.get_avg(): return True else: return False elif isinstance (other, (int, float)): if self.get_avg() < other: return True else: return False else: raise TypeError #__le__ means lower or equal <= def __le__(self, other): if isinstance (other, Student): if self.get_avg() <= other.get_avg(): return True else: return False elif isinstance (other, (int, float)): if self.get_avg() <= other: return True else: return False else: raise TypeError #__gt__ means greater than > def __gt__(self, other): if isinstance (other, Student): if self.get_avg() > other.get_avg(): return True else: return False elif isinstance (other, (int, float)): if self.get_avg() > other: return True else: return False else: raise TypeError #__ge__ means greater or equal >= def __ge__(self, other): if isinstance (other, Student): if self.get_avg() >= other.get_avg(): return True else: return False elif isinstance (other, (int, float)): if self.get_avg() >= other: return True else: return False else: raise TypeError s1 = Student('Ali', 18) print(s1) s1.add_course('Math', 17) s1.add_course('Physics', 12) print(s1) print(s1.get_avg()) s2 = Student('Sara', 22) s2.add_course('Art', 16) s2.add_course('Geography', 17) print(s2) if s2 > s1: print(f'{s2.name} is smarter than {s1.name}') elif s2 < s1: print(f'{s1.name} is smarter than {s2.name}') else: print(f'{s1.name} is as smart as {s2.name}') ''' Here we can compare the objects of class with each other but we can not compare them with int or float numbers so we should change methods to another shape. First one before change was like this: if self.get_avg() < other.get_avg(): return True else: return False and if we write code below we get an error because we cant comare them, for more clarification, run code below and replace these with those in the main code. if s1 < 10: print('Fail') ''' if s1 < 10: print('Fail') else: print('Pass') #And for comparing s1 with and string(that will arise an error) s1 < [15, 12] ''' I've commented multiple sections for continuing the lesson, so whereever you wanted, you can make comment a section and comment out another to see what is the out put or change the parameters for better understanding, hope you learn something. ''' '''Upvote if you liked'''

Object-Oriented Programming #9