Lesson 6: Making Decisions — Conditionals

AI models don't just crunch numbers; they use them to make decisions. Let's learn how to do that in Python.

In programming, decisions are made using conditionals: statements like if, elif (else if), and else. They allow our code to react differently depending on the data it receives.

Booleans and Comparisons

A Boolean is a data type that can only be True or False. We often get Booleans by comparing values:

Equals: == (e.g., 5 == 5 is True)
Not Equals: !=
Greater/Less Than: >, <
Greater/Less Than or Equal To: >=, <=

The `if` Statement

An if statement checks a condition. If the condition is True, it runs the code block indented underneath it.

accuracy = 0.92
if accuracy > 0.90:
print("Excellent model!")

Adding `else` and `elif`

We can chain conditions to handle multiple possibilities.

if accuracy > 0.90:
    print("Excellent")
elif accuracy > 0.75:
    print("Good")
else:
    print("Needs improvement")

Coding Challenge: Rule-Based Classifier

Before machine learning, early AI used "expert systems" that relied on hard-coded rules. Let's build a simple rule-based spam detector!

Create a variable email_text and assign it a string containing the words "free money" and "click here".
Write an if statement that checks if "free money" in email_text and "click here" in email_text.
If both conditions are true, print("SPAM DETECTED").
Otherwise, print("Not spam").

Hint: You can use the and keyword to combine two conditions.

Lesson 6: Making Decisions — Conditionals

Booleans and Comparisons

The if Statement

Adding else and elif

Coding Challenge: Rule-Based Classifier

Booleans and Comparisons

The if Statement

Adding else and elif

Coding Challenge: Rule-Based Classifier

The `if` Statement

Adding `else` and `elif`

The `if` Statement

Adding `else` and `elif`