Conditional Statements in Python

Conditional Statements in Python: Making Decisions with If-Else

One of the most important features in programming is **decision-making**—choosing different actions based on conditions. Python provides `if`, `else`, and `elif` statements to control program flow based on conditions.

Why Use Conditional Statements?

• Dynamic Behavior: Helps a program react differently to different inputs.
• Game Logic: Determines whether a player wins or loses.
• Data Filtering: Extracts relevant information based on conditions.
• User Interaction: Adapts program responses based on user choices.

The `if` Statement

The `if` statement **executes a block of code only if a condition is met**.

# Basic if statement
temperature = 30
if temperature > 25:
    print("It's a hot day!")

The `else` Statement

If the condition in `if` **is not met**, the `else` block runs.

# Using if-else
temperature = 18
if temperature > 25:
    print("It's a hot day!")
else:
    print("It's a cool day.")

The `elif` Statement

If you need **multiple conditions**, use `elif` (short for "else if").

# Using if-elif-else
temperature = 20
if temperature > 30:
    print("It's very hot!")
elif temperature > 25:
    print("It's warm.")
elif temperature > 15:
    print("It's mild.")
else:
    print("It's cold.")

Using Comparison Operators in Conditions

Python allows the use of **comparison operators** (`==`, `!=`, `>`, `<`, `>=`, `<=`) inside conditions.

# Checking for equality
password = "secure123"
if password == "secure123":
    print("Access granted!")
else:
    print("Access denied!")

Using Logical Operators (`and`, `or`, `not`)

You can combine conditions using logical operators.

• and - Both conditions must be true.
• or - At least one condition must be true.
• not - Negates a condition.

# Checking multiple conditions
age = 20
has_ID = True

if age >= 18 and has_ID:
    print("You can enter.")
else:
    print("Entry denied.")

Using Nested `if` Statements

`if` statements can be **nested** within each other for more complex decisions.

# Nested if conditions
score = 85

if score >= 50:
    print("Passed!")
    if score >= 80:
        print("Excellent performance!")

Conclusion

Conditional statements allow you to write programs that **make decisions dynamically**. Understanding `if`, `else`, and `elif` will help you create interactive and intelligent programs.

What kind of decision-making logic do you want to implement in your projects?