15. Python Special operators & Operator Precedence

 

Special operators:

1.      Identity operators.

2.     Membership operators.

 Identity operators

 Identity operators are (is, is not).

r1 is r2 = True

If it is show True then both ids pointing to the same address (ids).

r1 is not r2 = False

If it is show False then both ids not pointing to the same address (ids).

Ex:

a = 10

b = 10

l1 = (a is  b )

l2 = (a is not b)

print (l1,l2)

True False    # Result

Just remember all fundamental data types are immutable. (Fundamental data types are int, float, complex, bool,str) and object reusable concepts all are accepted. Except for complex data type. but remaining data types reusable not accepted.

Ex:

a= 10
b = 10
print(id(a),id(b))
list_1 = [10,20,30,40]
list_2 = [10,20,30,40]
print(id(list_1),id(list_2))

 

# Result

1761978432, 1761978432

24768200, 24888680

 Now apply ‘is’ and ‘==’.

a= 10
b = 10
print(a is b)
print(a is not b)
list_1 = [10,20,30,40]
list_2 = [10,20,30,40]
print(list_1 is list_2)
print(list_1 is not list_2)

 # Result

True               # ‘is’ operator meant for reference comparison. That’s why it is true.

False

False

True               # ‘is not’ operator meant for content comparison. That’s why it is true.

 Membership operators.

Membership operators are (in, not in).

If our requirement object is there in the sequence of variable data, then it’s true otherwise it’s false.

Ex:

word = 'smart program'

print('a' in word)

print('a' not in word)

print('pro' in word)

Result

True

False

True

Operator Precedence

If multiple operators are there, in which order, these operators are executed. In this sequence called operator precedence.

Ex:

print (4+2*3)

print((4+2)*3)

Result:

10

18

In first case ‘*’ is the first preference. So result look like

(4+2*3)

(4+6)

(10)

In second case () is the first preference. So result look like

((4+2)*3)

(6*3)

(18)

The operator precedences are listed below.

(upper group has higher precedence than the lower ones).

Operators	Meaning
()	Parentheses
**	Exponent
+x, -x, ~x	Unary plus, Unary minus, Bitwise NOT
*, /, //, %	Multiplication, Division, Floor division, Modulus
+, -	Addition, Subtraction
<<, >>	Bitwise shift operators
&	Bitwise AND
^	Bitwise XOR
|	Bitwise OR
==, !=, >, >=, <, <=,	Comparisons operators
=,+=,-=,*=	Relation operators
is, is not	Identity operators
in, not in	Membership operators
not	Logical NOT
and	Logical AND
or	Logical OR