Operators

What are operators?

Operators are symbols that perform operations on values. Think of them as the “verbs” of programming - they make things happen! You already know most operators from math class:

Calculate: +, -, *, /
Compare: >, <, ==
Combine: and, or, not

Arithmetic operators

These work just like your calculator:

# Basic math
print(10 + 3)   # 13 - Addition
print(10 - 3)   # 7  - Subtraction
print(10 * 3)   # 30 - Multiplication
print(10 / 3)   # 3.333... - Division (always gives float)

# Special operators
print(10 // 3)  # 3  - Floor division (rounds down)
print(10 % 3)   # 1  - Modulo (remainder)
print(10 ** 3)  # 1000 - Exponent (power)

Order of operations

Python follows math rules (PEMDAS):

result = 2 + 3 * 4      # 14 (not 20!)
result = (2 + 3) * 4    # 20 (parentheses first)

Comparison operators

These compare values and return True or False:

age = 18

print(age == 18)    # True  - Equal to
print(age != 21)    # True  - Not equal to
print(age > 17)     # True  - Greater than
print(age < 20)     # True  - Less than
print(age >= 18)    # True  - Greater than or equal
print(age <= 18)    # True  - Less than or equal

Don’t confuse = (assignment) with == (comparison)!

age = 18 stores 18 in age
age == 18 checks if age equals 18

Logical operators

These combine boolean values and conditions:

age = 25
has_license = True

# AND - both must be true
can_drive = age >= 16 and has_license
print(can_drive)  # True

# OR - at least one must be true
day = "Saturday"
is_weekend = day == "Saturday" or day == "Sunday"
print(is_weekend)  # True

# NOT - reverses the value
is_adult = age >= 18
is_child = not is_adult
print(is_child)  # False

Truth tables

Understanding how and, or, and not work:

# AND: Both must be True
print(True and True)    # True
print(True and False)   # False
print(False and False)  # False

# OR: At least one must be True  
print(True or False)    # True
print(False or False)   # False

# NOT: Flips the value
print(not True)         # False
print(not False)        # True

Short-Circuit Evaluation & Non-Booleans

In Python, logical operators (and, or) do not just return True or False. They return one of the actual evaluated values. Python evaluates values in a boolean context as either truthy or falsy:

Falsy values: False, None (Python’s null value), 0, 0.0, empty strings "", and empty lists/dictionaries.
Truthy values: Almost everything else (non-zero numbers, non-empty strings/lists).

How `and` behaves (Short-Circuit):

The and operator evaluates expressions from left to right and returns the first falsy value it encounters. If all values are truthy, it returns the last evaluated value.

print(2 and 3)       # 3 (both truthy, returns the last)
print(False and 3)   # False (first is falsy, returns it immediately)
print(0 and 3)       # 0 (0 is falsy, returns it)
print(None and 3)    # None (None is falsy, returns it)
print("" and 4)      # "" (empty string is falsy, returns it)

How `or` behaves (Short-Circuit):

The or operator evaluates from left to right and returns the first truthy value it encounters. If all values are falsy, it returns the last evaluated value.

print(2 or 3)        # 2 (first is truthy, returns it immediately)
print(False or 3)    # 3 (first is falsy, evaluates and returns next)
print(0 or None)     # None (both falsy, returns the last one)

Assignment shortcuts

These shortcuts update variables in place:

# Instead of:
score = score + 10

# Write:
score += 10

# Works with all operators
x = 10
x += 5    # x is now 15
x *= 2    # x is now 30

Common mistakes

Division always returns float

# Regular division
result = 10 / 2    # 5.0 (not 5)

# Integer division
result = 10 // 2   # 5

Order of operations

# Wrong
average = 10 + 20 + 30 / 3  # 40.0

# Right
average = (10 + 20 + 30) / 3  # 20.0

Confusing = and ==

# = assigns a value
age = 18

# == compares values
if age == 18:
    print("Just turned adult!")

Practice & Exercises

To reinforce what you’ve learned in this section (Arithmetic, Comparison, and Logical Operators), practice with these interactive notebooks:

Follow-Along Practice

Practice operators, PEMDAS rules, logical evaluations, and assignment shortcuts.💻 VS Code | 🚀 Colab | 📥 Download

Practice Exercises

Test your knowledge with hands-on exercises on floor division vs modulo, order of operations, and logical conditions.💻 VS Code | 🚀 Colab | 📥 Download

What’s next?

Once you are comfortable with Operators, let’s learn how to manipulate text strings!

String manipulation

Advanced text operations

Getting started

Data types

Working with data

Control flow

Data structures

Packing & Unpacking

What are operators?

Arithmetic operators

Order of operations

Comparison operators

Logical operators

Truth tables

Short-Circuit Evaluation & Non-Booleans

How `and` behaves (Short-Circuit):

How `or` behaves (Short-Circuit):

Assignment shortcuts

Common mistakes

Practice & Exercises

Follow-Along Practice

Practice Exercises

What’s next?

String manipulation

​What are operators?

​Arithmetic operators

​Order of operations

​Comparison operators

​Logical operators

​Truth tables

​Short-Circuit Evaluation & Non-Booleans

​How and behaves (Short-Circuit):

​How or behaves (Short-Circuit):

​Assignment shortcuts

​Common mistakes

​Practice & Exercises

Follow-Along Practice

Practice Exercises

​What’s next?

String manipulation

What are operators?

Arithmetic operators

Order of operations

Comparison operators

Logical operators

Truth tables

Short-Circuit Evaluation & Non-Booleans

How `and` behaves (Short-Circuit):

How `or` behaves (Short-Circuit):

Assignment shortcuts

Common mistakes

Practice & Exercises

What’s next?