Learn How to Write Conditional Statements in Python: Absolute Beginners Tutorial

Conditional statements are how your Python programs make decisions. They let your code choose between different paths depending on whether a condition is true or false — and understanding them unlocks nearly everything that makes programming useful.

Every useful program eventually needs to branch. Show a different message depending on a user's age. Charge a different price depending on a membership tier. Warn a user only if a value is out of range. All of these require conditionals. Python implements conditional logic through three keywords — if, elif, and else — and this tutorial walks through each one from first principles.

What Is a Conditional Statement?

A conditional statement tells Python to run a block of code only when a particular condition is True. If the condition is False, Python skips that block entirely. The simplest form uses just the if keyword.

age = 20

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

The line if age >= 18: is the condition. The colon at the end is required — it signals that a new indented block follows. The print statement is indented by four spaces, which is how Python knows it belongs to the if block. When age is 20, the condition is True and the message prints. Change age to 15 and nothing prints at all.

Adding an else Clause

An if statement on its own only handles the True case. To also handle the False case, add an else clause. The else block runs whenever the if condition is False.

age = 15

if age >= 18:
    print("You are an adult.")
else:
    print("You are a minor.")

Notice that else has no condition of its own — it is purely a fallback. Python runs exactly one of the two blocks and never both.

Comparison and Logical Operators

The expression inside an if statement is evaluated as either True or False. Python provides two families of operators for building these expressions: comparison operators and logical operators.

Comparison Operators

Comparison operators test the relationship between two values and return a boolean.

Logical Operators

Logical operators let you combine multiple conditions into a single expression. Python provides three: and, or, and not.

temperature = 22
is_raining = False

# and: both conditions must be True
if temperature > 15 and not is_raining:
    print("Good day for a walk.")

# or: at least one condition must be True
score = 45
if score >= 50 or score == 45:
    print("Close enough to pass.")

The elif Clause and Chained Conditions

When you have more than two possible outcomes, if and else are not enough. The elif keyword — short for "else if" — lets you check additional conditions in sequence. Python evaluates each clause from top to bottom and runs only the first one whose condition is True.

score = 74

if score >= 90:
    grade = "A"
elif score >= 80:
    grade = "B"
elif score >= 70:
    grade = "C"
elif score >= 60:
    grade = "D"
else:
    grade = "F"

print(f"Your grade is {grade}.")

With a score of 74, Python tests the first condition (score >= 90) — false. Then the second (score >= 80) — false. Then the third (score >= 70) — true. It assigns "C" and skips all remaining clauses including else.

Nested Conditionals

You can place an if statement inside another if block. Each inner level must be indented one additional level. Nested conditionals are useful when a secondary check only makes sense after a primary condition passes.

has_ticket = True
age = 16

if has_ticket:
    if age >= 18:
        print("Entry granted.")
    else:
        print("Ticket valid, but must be 18 or older.")
else:
    print("No ticket — entry denied.")

One-Line Conditional Expressions

Python supports a compact form called a conditional expression (sometimes called a ternary expression) that assigns a value based on a condition in a single line.

age = 20
status = "adult" if age >= 18 else "minor"
print(status)  # adult

The format is value_if_true if condition else value_if_false. This works well for simple assignments but can reduce readability when overused — avoid it for complex conditions.

"An if statement selects exactly one of its suites by evaluating each expression." — Python Language Reference

Python Learning Summary Points

1. The if keyword starts a conditional block. The condition must end with a colon, and the code to run must be indented by four spaces.
2. The else clause provides a fallback path that runs when the if condition is False. It takes no condition of its own.
3. The elif clause handles additional conditions between if and else. Python runs only the first matching branch and skips the rest.
4. Use == to test equality inside conditions. A single = is assignment and raises a SyntaxError when used in a condition.
5. Logical operators and, or, and not let you combine or invert conditions without nesting additional if statements.
6. Conditional expressions (value_if_true if condition else value_if_false) provide a concise single-line alternative for simple assignments.

Conditionals are the foundation of decision-making in any Python program. Once you are comfortable with if, elif, and else, the next step is exploring loops — which use the same indentation model to repeat code blocks based on conditions.