Operators

What Are Operators?

Operators are symbols or keywords that tell Python to perform an operation.

For example:

a = 10
b = 3
 
print(a + b)

Here, + is an operator that adds two values.

Python has several types of operators, including:

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

Let's look at each one.

Arithmetic Operators

Arithmetic operators are used for mathematical calculations.

Addition +

The + operator adds two values.

a = 10
b = 5
 
print(a + b)
 
# Output:
# 15

It can also be used with strings to join them together:

first_name = "John"
last_name = "Doe"
 
print(first_name + " " + last_name)
 
# Output:
# John Doe

Subtraction -

The - operator subtracts one value from another.

a = 10
b = 3
 
print(a - b)
 
# Output:
# 7

Multiplication *

The * operator multiplies values.

a = 10
b = 3
 
print(a * b)
 
# Output:
# 30

Division /

The / operator performs division.

a = 10
b = 3
 
print(a / b)
 
# Output:
# 3.3333333333333335

In Python, / returns a floating-point number, even when the result is a whole number:

print(10 / 2)
 
# Output:
# 5.0

Modulus %

The % operator returns the remainder after division.

print(10 % 3)
 
# Output:
# 1

This is useful when checking whether a number is even or odd:

print(10 % 2)
 
# Output:
# 0
 
print(7 % 2)
 
# Output:
# 1

If the remainder is 0, the number is evenly divisible by 2.

Floor Division //

The // operator performs floor division.

print(10 // 3)
 
# Output:
# 3

Regular division gives:

print(10 / 3)
 
# Output:
# 3.3333333333333335

Floor division gives the largest integer less than or equal to the result:

print(10 // 3)
 
# Output:
# 3

Negative Numbers with % and //

There is an important detail to know when working with negative numbers.

Python's % and // follow rules that can be surprising if you're coming from another programming language.

For example:

print(-7 % 3)
 
# Output:
# 2
 
print(-7 // 3)
 
# Output:
# -3

Python's % result has the same sign as the divisor.

So:

-7 % 3

gives:

2

Floor division also has an important detail.

// rounds down toward negative infinity, rather than toward zero.

Since:

-7 / 3

is approximately:

-2.333...

floor division gives:

print(-7 // 3)
 
# Output:
# -3

It does not give -2 because -3 is the next whole number when rounding down.

This behavior is especially useful to remember when working with negative numbers.

Exponentiation **

The ** operator raises a number to a power.

print(2 ** 3)
 
# Output:
# 8

This means:

2 × 2 × 2 = 8

Assignment Operators

Assignment operators are used to assign values to variables.

Basic Assignment =

The = operator assigns a value to a variable.

score = 10

Here, 10 is assigned to score.

Compound Assignment Operators

Python also provides shorthand operators for updating an existing variable.

For example:

score = 10
 
score += 5
 
print(score)
 
# Output:
# 15

This is equivalent to:

score = score + 5

Here are the common assignment operators:

For example:

number = 10
 
number += 5
print(number)
 
number *= 2
print(number)
 
# Output:
# 15
#30

Comparison Operators

Comparison operators compare two values.

They return either True or False.

For example:

age = 20
 
print(age == 20)
print(age > 18)
print(age < 18)
 
# Output:
# True
# True
# False

= vs ==

One of the most common mistakes for beginners is confusing = and ==.

= assigns a value:

age = 20

== compares two values:

age == 20

The first changes or assigns a variable.

The second checks whether the values are equal.

You'll use == frequently when writing conditional statements.

What Happens If You Use = in a Condition?

For example:

age = 18
 
if age = 18:
    print("You are 18")

This raises a SyntaxError.

Python does not allow assignment with = in this position. You need to use the comparison operator:

if age == 18:
    print("You are 18")

This is one of the mistakes Python catches before the program runs.

Logical Operators

Logical operators are used to combine or reverse conditions.

Python has three logical operators:

• and
• or
• not

and

and returns True when both conditions are true.

age = 25
 
print(age > 18 and age < 30)
 
# Output:
# True

Both conditions are true:

age > 18
age < 30

or

or returns True when at least one condition is true.

age = 25
 
print(age < 18 or age > 20)
 
# Output:
# True

The second condition is true, so the overall result is True.

not

not reverses a Boolean value.

is_logged_in = True
 
print(not is_logged_in)
 
# Output:
# False

We'll use logical operators more when working with conditional statements.

Membership Operators

Python has two membership operators:

• in
• not in

They check whether a value exists inside a sequence or collection.

For example, with a string:

message = "Hello"
 
print("H" in message)
print("x" in message)
 
# Output:
# True
# False

You can also use not in:

message = "Hello"
 
print("x" not in message)
 
# Output:
# True

Membership operators are especially useful when working with strings, lists, and other collections.

We'll explore them more when we learn about lists and collections.

Identity Operators

Python also has two identity operators:

• is
• is not

Identity operators check whether two references point to the same object.

For example:

a = None
 
print(a is None)

Output:

True

is is different from ==.

== checks whether two values are equal.

is checks whether two references refer to the same object.

A common use is checking for None:

value = None
 
if value is None:
    print("No value")

We'll explore objects and identity in more detail later.

Bitwise Operators

Bitwise operators work with the individual bits of integer values.

Python provides these bitwise operators:

For example:

a = 5
b = 3
 
print(a & b)
 
# Output:
# 1

Bitwise operators are commonly used in areas such as low-level programming, permissions, flags, and performance-sensitive code.

You don't need to memorize them when you're just starting with Python, but it's useful to know they exist.

Operator Precedence

When an expression contains multiple operators, Python follows a specific order when evaluating them.

For example:

result = 10 + 2 * 3
 
print(result)
 
# Output:
# 16

Python performs multiplication before addition:

2 * 3 = 6
10 + 6 = 16

You can use parentheses to make the order explicit:

result = (10 + 2) * 3
 
print(result)
 
# Output:
# 36

A simplified order to remember is:

1. Parentheses
2. Exponentiation **
3. Multiplication, division, floor division, and modulus
4. Addition and subtraction
5. Comparisons
6. not
7. and
8. or

When in doubt, use parentheses. They make your code easier to read and remove ambiguity.

Operators and Conditional Statements

Operators become especially useful when combined with conditional statements.

For example:

age = 20
 
if age >= 18:
    print("You are an adult")

Here:

age >= 18

is a comparison that produces either True or False.

The if statement then uses that result to decide whether to run the code inside it.

We'll explore conditional statements in the next lesson.

Quick Reference

👉 Next tutorial: Python Conditional Statements