Introduction to Conditional Statements

Conditional statements allow your program to make decisions based on conditions. This is a fundamental concept in programming.

In this lesson, you’ll learn how to write conditional statements in Python using if, elif, and else.

What are Conditional Statements?

Conditional statements let the program execute certain parts of code only when specific conditions are met. For example:

Here, the program checks if the temperature is greater than 30. If true, it prints "It's hot outside!".

# Conditional statement example
temperature = 35
if temperature > 30:
    print("It's hot outside!")

Writing if Statements

An if statement checks a condition and executes the code block if the condition is true. For example:

# Writing an if statement
x = 10
if x > 5:
    print("x is greater than 5")

Adding else Statements

An else statement runs when the condition in the if statement is false. For example:

# Using else statement
x = 3
if x > 5:
    print("x is greater than 5")
else:
    print("x is less than or equal to 5")

Using elif for Multiple Conditions

The elif (short for 'else if') statement checks additional conditions if the previous ones are false. For example:

# Using elif for multiple conditions
grade = 85
if grade >= 90:
    print("A")
elif grade >= 80:
    print("B")
else:
    print("C")

Indentation in Python

Python uses indentation to define blocks of code. Make sure to indent consistently to avoid errors. For example:

# Indentation example
x = 10
if x > 5:
    print("x is greater than 5")

Nesting Conditionals

You can nest conditionals inside each other for more complex logic:

# Nested conditionals
x = 10
y = 5
if x > 5:
    if y < 10:
        print("x is greater than 5 and y is less than 10")

Common Errors in Conditionals

Here are some common mistakes to avoid:

• Forgetting to use colons (:) at the end of conditional statements.
• Incorrect or inconsistent indentation.
• Misusing elif or else statements.

What Did We Learn?

In this lesson, you learned:

• How to write if, elif, and else statements.
• The importance of indentation in Python.
• How to use nested conditionals for complex logic.

Great job! Let’s move on to the next topic.