Python- Operators(Contd)-6(c)

Good Morning Dear students

I hope that you got enough time to take a review of the topics covered earlier. Don't forget these are linked topics.

By the end of this session you will be able to 

• Understand the working of the various logical operators.
• Predict the output of expressions involving Logical Operators.
• Understand the precedence of operators in an expression and predict the output.

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Python Logical Operators

There are following logical operators supported by Python language. Assume variable a holds 10 and variable b holds 20 then

Operator	Description	Example
and Logical AND	If both the operands are true then condition becomes true.	(a and b) is true.
or Logical OR	If any of the two operands are non-zero then condition becomes true.	(a or b) is true.
not Logical NOT	Used to reverse the logical state of its operand.	Not(a and b) is false.

  Logical operators are used to combine conditional statements:

(Try and predict the result in the following examples. To check whether you are right or not , click on "Try it" and see the result)                      

Operator	Description	Example	Try it
and	Returns True if both statements are true	x < 5 and  x < 10	Try it »
or	Returns True if one of the statements is true	x < 5 or x < 4	Try it »
not	Reverse the result, returns False if the result is true	not(x < 5 and x < 10)	Try it »

Example #1: Logical Operators in Python

x = True
y = False

# Output: x and y is False
print('x and y is',x and y)

# Output: x or y is True
print('x or y is',x or y)

# Output: not x is False
print('not x is',not x)

Python Operators Precedence

The following table lists all operators from highest precedence to lowest.

Sr.No.	Operator & Description
1	** Exponentiation (raise to the power)
2	~ + - Complement, unary plus and minus (method names for the last two are +@ and -@)
3	* / % // Multiply, divide, modulo and floor division
4	+ - Addition and subtraction
5	>> << Right and left bitwise shift
6	& Bitwise 'AND'
7	^ | Bitwise exclusive `OR' and regular `OR'
8	<= < > >= Comparison operators
9	<> == != Equality operators
10	= %= /= //= -= += *= **= Assignment operators
11	is is not Identity operators
12	in not in Membership operators
13	not or and Logical operators

(operators in RED are yet to be done. )

EXERCISE
Please do the work in your registers, click the photo and submit on git@stcolumbas.edu.in

1. What are logical operators? Where are they used?
2. Differentiate between AND and OR logical operators.
3. What is the purpose of the NOT logical operator?
4. What do you mean by "Precedence of operators"? How does it impact and expression in Python?
5. Predict the output of the following python statements:

a = True
b = False
print(('a and b is',a and b))
print(('a or b is',a or b))                                            print(('not a is',not a))