Using Python OR Operator with Boolean Expression

Python OR operator returns True in any one of the boolean expressions passed is True.

Example: Or Operator with Boolean Expression

bool1 = 2>3
bool2 = 2<3

print('bool1:', bool1)
print('bool2:', bool2)

# or operator
OR = bool1 or bool2
print("OR operator:", OR)

bool1: False
bool2: True
OR operator: True

Using Python OR Operator in if

We can use the OR operator in the if statement. We can use it in the case where we want to execute the if block if any one of the conditions becomes if True.

Example: Or Operator with if statement

# or operator with if
def fun(a):
    if a % 5 == 0 or a % 3 == 0:
        print('a either a multiple of 3 or 5')
    else:
        print('a is not a multple of 3 or 5')


# driver code
fun(10)
fun(22)
fun(5)

a either a multiple of 3 or 5
a is not a multple of 3 or 5
a either a multiple of 3 or 5

Python OR Operator – Short Circuit

The Python Or operator always evaluates the expression until it finds a True and as soon it Found a True then the rest of the expression is not checked. Consider the below example for better understanding.

Example: Short Circuit in Python OR Operator

# short circuit in Python or operator
def true():
    print("Inside True")
    return True

def false():
    print("Inside False")
    return False

case1 = true() or false()
print("Case 1")
print(case1)
print()

case2 = true() or true()
print("Case 2")
print(case2)
print()

case3 = false() or false()
print("Case 3")
print(case3)
print()

case4 = false() or true()
print("Case 4")
print(case4)

Inside True
Case 1
True

Inside True
Case 2
True

Inside False
Inside False
Case 3
False

Inside False
Inside True
Case 4
True

From the above example, we can see that the short circuit or lazy evaluation is followed. In case1 and case2, the second expression is not evaluated because the first expression returns True, whereas, in case3 and case4 the second expression is evaluated as the first expression does not returns True.