Day05-Python Operators # 2

PART # 2

Logical Operators:

Logical operators are used to combine conditional statements. It tells whether the statement is True or False.

• and operator: Returns True if both statements are true

x = 5
print(x > 3 and x < 10) #output= True
# returns True => because 5 is greater than 3 and 5 also is less than 10

• or operator: Returns True if one of the statements is true

x = 5
print(x > 3 or x < 4)  #output = True
# returns True => because one of the conditions are true --> 5 is greater than 3
# but 5 is not less than 4

• not operator: Reverse the result, returns False if the result is true and returns True if the result is false.

x = 5
print(not(x > 3 and x < 10))
# 5 is greater than 3 and 5 also is less than 10
# returns False => because both statements are true

Identity Operators:

Identity operators are used to compare the objects, not if they are equal, but if they are actually the same object, with the same memory location:

• is operator:

x = ["apple", "banana"]
y = ["apple", "banana"]
z = x

print(x is z) #returns True 
# because z is the same object as x

print(x is y) #returns False
# because x is not the same object as y, even if they have the same content

print(x == y) #returns True 
# to demonstrate the difference betweeen "is" and "==": 
# this comparison returns True because x is equal to y

• is not operator:

x = ["apple", "banana"]
y = ["apple", "banana"]
z = x

print(x is not z) # returns False
# because z is the same object as x

print(x is not y) # returns True 
# because x is not the same object as y, even if they have the same content

print(x != y)  # returns False
# to demonstrate the difference betweeen "is not" and "!=": 
# this comparison returns False because x is equal to y

Python Membership Operators:

• in operator:

x = ["apple", "banana"]  
print("banana" in x) # returns True
# returns True => because a sequence with the value "banana" is in the list

• not in operator:

x = ["apple", "banana"]
print("pineapple" not in x) # returns True 
# returns True => because a sequence with the value "pineapple" is not in the list

Bitwise Operators:

Bitwise operators are used to compare (binary) numbers:

• AND operator (&):

The bitwise AND operator & returns a binary number whose bits are set to 1 only if the corresponding bits of both its operands are 1

print(6 & 3) #output= 2

In this case, 6 and 3 are represented in binary as 110 and 011, respectively. Performing a bitwise AND operation on these two numbers results in 010, which is equivalent to the decimal number 2. Therefore, the output of the given Python code is 2.

• OR operator ( | ):

The bitwise OR operator | returns a binary number whose bits are set to 1 if either of the corresponding bits of its operands is 1.

print(6 | 3)  #output= 7

In this case, 6 and 3 are represented in binary as 110 and 011, respectively. Performing a bitwise OR operation on these two numbers results in 111, which is equivalent to the decimal number 7. Therefore, the output of the given Python code is 7.

• XOR operator ( ^ ):

The bitwise XOR operator ^ returns a binary number whose bits are set to 1 only if the corresponding bits of its operands are different.

print(6 ^ 3)   #output= 5

In this case, 6 and 3 are represented in binary as 110 and 011, respectively. Performing a bitwise XOR operation on these two numbers results in 101, which is equivalent to the decimal number 5. Therefore, the output of the given Python code is 5.

• NOT operator (~):

The tilde operator ~ in Python is a unary operator that performs bitwise inversion. It reverses all the bits in a given number, i.e., all ones become zeros and all zeros become ones

print(~3)    #output= -4

In this case, the number 3 is represented in binary as 011. Inverting the bits of 3 results in 100, which is equivalent to the decimal number -4 1. Therefore, the output of the given Python code is -4.

• Zero fill left shift opera1tor (<<):

The bitwise left shift operator << shifts the bits of its first operand to the left by the number of positions specified in its second operand.

print(3 << 2)  #output= 12

In this case, 3 is represented in binary as 011. Shifting the bits of 3 two positions to the left results in 1100, which is equivalent to the decimal number 12. Therefore, the output of the given Python code is 12.

• Signed right shift (>>):

The bitwise right shift operator >> shifts the bits of its first operand to the right by the number of positions specified in its second operand.

print(8 >> 2)   #output= 2

In this case, 8 is represented in binary as 1000. Shifting the bits of 8 two positions to the right results in 0010, which is equivalent to the decimal number 2. Therefore, the output of the given Python code is 2.

Quick Quiz:

Example # 1

print((6 + 3) - (6 + 3)) #output =0
# Parenthesis have the highest precedence, and need to be evaluated first.
# The calculation above reads 9 - 9 = 0

Example # 2

print(100 + 5 * 3) #output = 115

# Multiplication has higher precedence than addition, and needs to be evaluated first.
# The calculation above reads 100 + 15 = 115

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