class MyClass: # myClass, my_class
  pass

Instance

a = MyClass() # a -> instance of the class
b = MyClass()
print(a,b)

<__main__.MyClass object at 0x7d042e125930> <__main__.MyClass object at 0x7d042e126050>

Object Initialization

class MyClass: # myClass, my_class
  def __init__(self, x, y): # constructor
    self.x = x
    self.y = y

  def get_x(self): # getter
    return self.x

  def set_x(self, x): # setter
    if x < 0:
      raise ValueError("x cannot be negative")
    self.x = x

a = MyClass(x=3,y=5)
# print(a.x) # direct
a.get_x() # indirect
a.x = 12 # direct
print(a.x)
a.set_x(-3) # indirect
print(a.x)

12

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-36-51ebe11f7abd> in <cell line: 19>()
     17 a.x = 12 # direct
     18 print(a.x)
---> 19 a.set_x(-3) # indirect
     20 print(a.x)

<ipython-input-36-51ebe11f7abd> in set_x(self, x)
      9   def set_x(self, x): # setter
     10     if x < 0:
---> 11       raise ValueError("x cannot be negative")
     12     self.x = x
     13 

ValueError: x cannot be negative

Additonal methods

class MyClass: # myClass, my_class
  pi = 3.14
  def __init__(self, x, y): # constructor
    self.x = x
    self.y = y
    self._private_var = 0
    self._sum_var = None
    self._sum = self._private_func()


  def get_x(self): # getter
    return self.x

  def get_y(self): # getter
    return self.y

  def set_x(self, x): # setter
    if x < 0:
      raise ValueError("x cannot be negative")
    self.x = x

  def set_x(self, y): # setter
    self.y = y

  def __str__(self):
    return f"x: {self.x}, y: {self.y}"

  def __repr__(self):
    return f"MyClass(x={self.x}, y={self.y})"

  def _private_func(self):
    self._sum_var = self._private_func_var(10)
    return self.x + self.y

  def _private_func_var(self,z):
    return self.x + self.y + z

  def get_sum(self):
    ''' Returns the sum of x and y '''
    return self._sum

  def __call__(self):
    pass

a = MyClass(x=3,y=5)
b = MyClass(x=6,y=7)
print(a,'; ',b)
print(a.pi, b.pi)

x: 3, y: 5 ;  x: 6, y: 7
3.14 3.14

Set of integers

New variable that includes integers (only)

• Init: emptry variable
• Each number can show up in variable only once
• Internal representation - list
• Methods:
  • insert
  • member
  • remove
  • printable

 class intSet():
  def __init__(self):
    self.s = []

  def insert(self, e):
    ''' Insert e into set
    e must be an integer
    e must not be already in the set
    '''
    if type(e) != int:
      print("Not an integer")
    elif not self.member(e):
      self.s.append(e)
    else:
      print("Already in set")

  def member(self, e):
    return e in self.s

  def remove(self, e):
    #if self.member(e):
    if intSet.member(self,e):
      self.s.remove(e)
    else:
      print("Not in set")

  def __str__(self):
    self.s.sort()
    # return '{' + ', '.join([str(e) for e in self.s]) + '}'
    result = ''
    for e in self.s:
      result += str(e) + ', '
    return '{' + result[:-2] + '}'

  def __add__(self, other):
    result = intSet()
    for e in self.s:
      result.insert(e)
    for e in other.s:
      result.insert(e)
    return result

s=intSet()
# print(s)
s.insert(1)
s.insert(1)
s.insert(2)
s.insert(3)
# print(s)
s.remove(2)
s.remove(4)
print(s)
z = intSet()
z.insert(3)
z.insert(4)
print(z)
print(s+z)

Already in set
Not in set
{1, 3}
{3, 4}
Already in set
{1, 3, 4}