Python Operators

Python Operators Overview

• Week 3, Lesson 1 introduces Python Operators.

Learning Objectives

• The concept of Python Operators can be explained
• Types of Python Operators can be utilized

Definition and Categories

• An operator is a symbol that performs operations on variables and values.
• In arithmetic operations, numbers are called operands.
• An operator defines the operation performed between two operands.
• Python operators are used to perform operations on variables and values
• The '+' (Addition) operator adds two values ​​together.
• The Assignment Operator (=) assigns a value to a variable.
• Example: x = 5 assigns the value 5 to the variable x.

Groups of Python Operators:

• Arithmetic Operators
• Assignment Operators
• Comparison Operators
• Logical Operators
• Bitwise Operators
• Membership operators
• Identity operators

Arithmetic Operators

• Used with numeric values ​​for common mathematical operations.
• Addition: x + y
• Subtraction: x - y
• Multiplication: x * y
• Division: x / y
• Modulus (Division Remainder): x % y
• Floor division: x // y
• Exponentiation: x ** y

Arithmetic Operations

• Typical arithmetic operations operate on two numbers.
• The code print(x + y) adds numbers; for x = 5 and y = 3, Result: is 8
• The code print(x - y) subtracts numbers; for x = 5 and y = 3, the Result: is 2
• The code print(x * y) multiplies numbers; for x = 5 and y = 3, the Result: is 15
• The codeprint(x / y) divides numbers; for x = 5 and y = 3, the Result: is 1.6666…
• The code print(x % y) returns the division remainder; for x = 5 and y = 3, the Result: is 2
• The code print(x // y) returns the division quotient; for x = 5 and y = 3, the Result: is 1
• The code print(x ** y) returns the exponent; for x = 5 and y = 3, the Result: is 125

Concept of Assignment Operators

• Assignment operators assign values to variables
• Assignment:x = y
• Addition Assignment: x += y is the same as x = x + y
• Subtraction Assignment: x -= y which is the same as x = x - y
• Multiplication Assignment: x *= y which is the same as x = x * y
• Division Assignment: x /= y which is the same as x = x / y
• Modulus Assignment: x %= y which is the same as x = x % y
• Floor division Assignment: x //= y which is the same as x = x // y
• Exponentiation Assignment: x **= y which is the same as x = x ** y
• Assigning AND: x &= 3 which is the same as x = x & 3
• Assigning OR: x |= 3 which is the same as x = x | 3
• Assigning XOR: x ^= 3 which is the same as x = x ^ 3
• Shift right assignment: x >>= 3 which is the same as x = x >> 3
• Shift left assignment: For example print(x := 3) will print(x) and set x = 3

Examples of Assignment Operators

• Arithmetic assignment operators are a shorthand way of performing arithmetic operations and assigning the result in one step.
• += and -= are the two most common arithmetic assignment operators
• For x = 10, x += 5 results in x = 15
• For x = 10, x -= 5 results in x = 5
• For x = 5, x *= 5 results in x = 50
• The division assignment (/=) operator performs division on the two operands and assigns the result to the left operand
• For x = 20, x /= 2 results in x = 10.0
• For x = 20,x %= 7 results in x = 3.0
• For x = 20, x //= 2 results in x = 1.0

Comparison Operators

• Comparison operators are used in logical statements to determine equality or difference between variables or values.
• Comparison and logical operators are used to test for true or false.
• Equal: x == y
• Not equal: x != y
• Greater than: x > y
• Less than: x < y
• Greater than or equal to: x >= y
• Less than or equal to: x <= y
• If x = 5 and y = 3, the code print(x > y) returns True
• If x = 5 and y = 3, the code print(x <= y) returns False
• If x = 5 and y = 3, the codeprint(x == y) returns False
• If x = 5 and y = 3, the code print(x != y) returns True

Logical Operators

• Logical operators determine the logic between variables or values.
• and: Returns True if both statements are true
• or: Returns True if one of the statements is true
• not: Reverses the result; returns False if the result is true
• With x = 5, the code print(x > 3 and x < 10) returns True because 5 is greater than 3 AND 5 is less than 10
• With x = 5, the code print(x > 3 or x < 4) returns True because one of the conditions are true; 5 is greater than 3
• With x = 5, the code print(not(x > 3 and x < 10)) returns False because not is used to reverse the result

Concept of Bitwise Operators

• Bitwise operators compare (binary) numbers.
• & (AND): Sets each bit to 1 if both bits are 1
• | (OR): Sets each bit to 1 if one of two bits is 1
• ^ (XOR): Sets each bit to 1 if only one of two bits is 1
• ~ (NOT): Inverts all the bits
• << (left shift): Shifts left by pushing zeros in from the right, letting the leftmost bits fall off
• >> (right shift): Shifts right by pushing copies of the leftmost bit in from the left, letting the rightmost bits fall off
• Binary and decimal results of bitwise operations
• 5 & 1: binary 0101 & 0001= binary 0001 = decimal 1
• 5 | 1: binary 0101 | 0001 = binary 0101 = decimal 5
• 5 ^ 1: binary 0101 ^ 0001= binary 0100 = decimal 4
• ~5: binary ~0101 = binary 1010 = decimal 10
• 5 << 1: binary0101 << 1 = binary 1010 = decimal 10
• 5 >> 1: binary0101 >> 1 = binary 0010 = decimal 2

Examples of Bitwise Operators

• Bitwise AND sets each bit to 1 if both bits are 1.
  • For print( 0 & 1 ) the Result: is 0
• Bitwise OR sets each bit to 1 if one of two bits is 1
• For print( 0 | 1 ) the Result: is 1
• Bitwise Left Shift shifts left by pushing zeros in from the right
• For x = 5, print( x << 1) results in 10
  • x's binary number '0101' becomes '1010' which equals 5 * 2
• Bitwise Right Shift shifts right by pushing copies of the leftmost bit in from the left
• For y = 8, print( y >> 1) results in 4
  • y's binary number ‘1000' becomes ‘0100' which is equal to 8 / 2