OBJECT IN PYTHON

The concept of allocating memory space for non-static variable of a class at runtime dynamically is known as an object. We can create ‘n’ number of objects for one class. After creating the object, address of object will be stored in variable and we call that variable as a reference variable. From that variable we can put the data into object, we can get data and also call the methods on that object.

Example –

def display():
    print 'hi'
class X:
    def __init__(self,i,j):
        self.i=i
        self.j=j
    def display(self):
        print self.i
        print self.j
X1=X(100,400)

print X1

print id(X1)

print hex(id(X1)).upper()
X1.display()
X2=X(200,500)

print X2

print hex(id(X2)).upper()
X2.display()
display()

Output –

<__main__.X instance at 0x02623288>

39989896

0X2623288

100

400

<__main__.X instance at 0x026232B0>

0X26232B0

200

500

hi

Example –

class InsufficientFund(Exception):
    """ balance not available """

class Customer:
    cbname='sbi'
    def __init__(self,cname,cadd,cacno,cbal):
        self.cname=cname
        self.cadd=cadd
        self.cacno=cacno
        self.cbal=cbal
    def deposit(self,damt):
        self.cbal=self.cbal+damt
    def withdraw(self,wamt):
        if wamt>self.cbal:
            raise InsufficientFund
        self.cbal = self.cbal - wamt
    def display(self):
        print self.cname
        print self.cadd
        print self.cacno
        print self.cbal
        print self.cbname
C1=Customer('rakesh','guwahati',8001,100000.00)
C1.display()
C1.deposit(10000.00)

try:
    C1.withdraw(70000.00)

except:
    print 'Insufficient fund in your account'

C1.display()
C2=Customer('bikash','silpukhuri',8002,1000.00)
C2.display()
C2.deposit(1000.00)

try:
    C2.withdraw(4000.00)

except:
    print 'Insufficient fund in your account'

C2.display()

Output –

rakesh

guwahati

8001

100000.0

sbi

rakesh

guwahati

8001

40000.0

sbi

bikash

silpukhuri

8002

1000.0

sbi

Insufficient fund in your account

bikash

silpukhuri

8002

2000.0

sbi

Adding static and non-static variables to the class and object from outside of class.

Example –

class Abc:
    x=100
    def __init__(self):
        self.y=2000
        self.z=3000

Abc.p=4000

print Abc.x

print Abc.p
D1=Abc()
D1.q=5000

D1.r=6000

print D1.y

print D1.z

print D1.q

print D1.r
D2=Abc()

print D2.y

print D2.z

Output –

100

4000

2000

3000

5000

6000

2000

3000


Removing static and non-static variables from class and object

Example –

class Abc:
    x=100
    def __init__(self):
        self.y=2000
        self.z=3000

print Abc.x

del Abc.x
D1=Abc()

print D1.y

print D1.z

del D1.y

del D1.z
D2=Abc()

print D2.y

print D2.z

Output –

100

2000

3000

2000

3000

Note - If static variable is removed then it is removed for all objects of that class. But non-static variable is removed only for that particular class.