Introduction to Conditional Logic

TL;DR

Conditional logic lets your programs make decisions and do different things based on whether certain conditions are true or false. It's like a choose-your-own-adventure for your code, guiding its path through various possibilities. The most common way to do this is with if, elif, and else statements, which let you check conditions in a sequence.

1. The Mental Model

Imagine you're following a recipe. Sometimes it says, "If it's too thick, add more milk." Other times, it's "If using an electric mixer, beat for 3 minutes; otherwise, stir by hand for 5." Conditional logic in programming works the same way: your code checks a situation and then chooses which instructions to follow next.

2. The Core Material

Programs often need to adapt. Maybe you want to display a different message based on the time of day, or calculate a discount only if a customer spends over a certain amount. This is where conditional logic comes in.

The fundamental idea is always: "If this is true, then do that."

In Python, the primary tools for conditional logic are if, elif, and else statements.

The if Statement

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The if statement is the simplest form. It checks a condition, and if that condition is true, it executes a block of code.

temperature = 25

if temperature > 20:
    print("It's a warm day!")

In this example, temperature > 20 is the condition. Since 25 is greater than 20, the condition is True, and the print() statement runs. If temperature were 15, the condition would be False, and nothing would be printed.

Notice the colon : after the condition and the indentation of the print() line. Indentation is crucial in Python; it defines the block of code that belongs to the if statement.

The else Statement

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