Conditional Execution — Lesson 3: More than two outcomes

New skill: Elif chains and mutually exclusive ranges
Previously learned: Unit 04 — comparisons and Boolean logic

Why this matters

Use elif to check another condition after the first fails. In a chain, Python selects the first true branch.

Study this example

def light(status):
    if status >= 80:
        return 'Green'
    elif status >= 40:
        return 'Yellow'
    else:
        return 'Red'

A value of 90 chooses the first branch. A value of 60 skips the first but matches the second. A value of 20 reaches else.

Before moving on, predict the result of the program or function. Then run it and compare.

Check your understanding

Why does light(95) return ‘Green’ rather than ‘Yellow’ even though 95 is also >= 40?

Common mistake

Always order comparisons with overlapping ranges carefully; earlier matching branches win.

Practice

Complete classify_score(score) to return 'Gold' for 90 or above, 'Silver' for 70 through 89, and 'Bronze' for anything below 70.

Public example 1

Input

classify_score(92)

Output

'Gold'

Public example 2

Input

classify_score(70)

Output

'Silver'

Public example 3

Input

classify_score(69)

Output

'Bronze'

Public example 4

Input

classify_score(90)

Output

'Gold'

Open the Python starter

Hint 1

Check the highest threshold first.

Hint 2

After scores of 90+ are handled, what does >= 70 mean?

Hint 3

Use `else` for every remaining score.

Reflection

Explain why your solution works and describe one boundary case you tried.