Python Operators: Assignment and Special Operators

Assignment operators:

• Assignment operators are used in Python to assign values to variables. 
• a = 5 is a simple assignment operator that assigns the value 5 on the right to the variable a on the left. 
• There are various compound operators in Python like a += 5 that adds to the variable and later assigns the same. It is equivalent to a = a + 5.

Note:

• Python not support the post increment and decrement,pre increment and decrement. but this mechanism achieve indirectly by using assignment operators.

Special operators:

Python language offers some special type of operators,they are

• Identity operators

• Membership operators

These operators are not supported other languages

Identity operators:

• Identity operators  are used to compare the address of the objects which are pointed by the operands.

Example1:

x=10

y=4

print(id(x))

print(id(y))

print(x is y)

print(x is not y)

Output:

1812472816

1812472624

False

True

Example2:

a=100

b=100

print(id(a))

print(id(b))

print(a is b)

print(a is not b)

Output:

1812475696

1812475696

True

False

Note:

above two examples are immutable objects.

Example3:

p=[10,20,30,40]

q=[10,20,30,40]

print(id(p))

print(id(q))

print(p is q)

print(p is not q)

Output:

55103816

55172232

False

True

Note:

p and q are mutable objects.mutable objects contains same content but having different address.

Membership operators

• Membership operators are used to search for the given element in the given object.

• Objects like list,tuple,set,dict.

• These membership operators feature takes from SQL .

Example1:

x=[10,20,30,40,50]

print(10 in x)

print(60 in x)

print(20 not in x)

print(100 not in x)

Output:

True

False

False

True

Example2:

name="sivakrishna"

print('i' in name)

print('a' in name)

print('y' not in name)

print('k' not in name)

Output:

True

True

True

False

Operator presidency:

Example:

a=20

b=10

c=15

d=5

e=0

e=(a+b)*c/d

print("value of (a+b)*c/d is: ",e)

e=((a+b)*c)/d

print("value of ((a+b)*c)/d is: ",e)

e=(a+b)*(c/d)

print("value of (a+b)*(c/d) is: ",e)

e=a+(b*c)/d

print("value of (a+b)*c/d is: ",e)

Output:

value of (a+b)*c/d is:  90.0

value of ((a+b)*c)/d is:  90.0

value of (a+b)*(c/d) is:  90.0

value of (a+b)*c/d is:  50.0