Operators in Python

An operator in Python is a special symbol that operates on one or more values, known as operands. For example, in the expression 5 + 3, the + symbol is the operator, and 5 and 3 are the operands.

Python provides several categories of operators, each designed for a specific type of task: performing calculations, assigning values, comparing data, combining conditions, working with binary numbers, checking membership, and writing short conditional expressions. This lesson explains each category in detail, with a clear definition, syntax, and examples for every operator.

1. Arithmetic Operators

Definition: Arithmetic operators are used to perform mathematical calculations such as addition, subtraction, multiplication, and division.

a = 10
b = 3
print(a / b)    # 3.3333333333333335
print(a // b)   # 3
print(a % b)    # 1

Note: Division (/) always produces a float value, whereas floor division (//) produces a whole number by discarding the decimal portion.

2. Assignment Operators

Assignment operators are used to assign values to variables. Python also provides compound assignment operators that combine an arithmetic operation with assignment in a single step.

x = 10
x += 5
print(x)   # 15

3. Comparison Operators

Comparison operators are used to compare two values. The result of a comparison is always a Boolean value, either True or False.

x = 7
y = 10
print(x == y)   # False
print(x < y)    # True

4. Logical Operators

Logical operators are used to combine two or more conditions and return a single Boolean result.

age = 20
has_id = True
print(age >= 18 and has_id)   # True

5. Bitwise Operators

Bitwise operators perform operations on the binary (bit-level) representation of integers, rather than on their decimal values.

a = 5   # binary: 0101
b = 3   # binary: 0011
print(a & b)   # 1
print(a | b)   # 7

Note: Bitwise operators are used less frequently in beginner-level programs but are important in areas such as data encoding, permissions, and performance optimization.

6. Membership Operators

Membership operators are used to test whether a value exists within a sequence, such as a string, list, or tuple.

name = "Kathmandu"
print("K" in name)       # True
print("z" not in name)   # True

Practice Questions

• Differentiate between / and // with a suitable example.
• Rewrite the statement x = x + 10 using a compound assignment operator.
• Identify the error in the following code and correct it:

   if score = 90:
       print("Excellent")

• Evaluate 5 & 3 and explain the result using binary representation.
• Write a ternary expression to check whether a number n is even or odd. Evaluate "a" in "banana" and "z" not in "banana".
• Write a logical expression to check whether a student is eligible for a scholarship, given that marks must be above 80 and attendance must be above 90 percent.