if, elif, and else

Scenario: A monitor must label response times healthy, slow, or critical.

New words, in plain English

• Control flow - the order in which instructions run
• Condition - an expression treated as True or False
• Branch - one possible path through a decision

An if tests first, elif adds ordered alternatives, and else catches everything remaining. Indentation defines each branch.

Analogy: A Python program is like a clear set of instructions for a careful helper: names label things, indentation groups steps, and errors explain where the helper became confused.

A small, real example

ms = 850
if ms >= 1000:
    label = "critical"
elif ms >= 500:
    label = "slow"
else:
    label = "healthy"

Tip: Put narrower or higher thresholds before broader ones.

Goal: Practice this idea in the py-conditionals-loops challenge at /labs/python. Fix the broken program, run it yourself, then use check to prove the real end state.