lesson 18 Conditional Logic · beginner

An if inside an if

The inner if runs only when the outer test is already true.

You'll be able to

Indent a second if under the first
Give the inner if its own else
See that the inner test is skipped when the outer test is false

The idea

Sometimes the second question only matters after the first one is true. A return is only worth checking for condition if it is still inside the return window. Put that second if indented under the first.

The inner else belongs to the inner if. It must line up with that inner if, not with the outer one. and can ask both questions at once, but then you get only one answer for "no". Nesting lets each "no" say something different.

Run each example to see what it prints. Running examples doesn't count toward progress.

example-1.py · Packed, and expensive enough

price = 20
status = "packed"
if price >= 15:
    if status == "packed":
        print("Ship")
    else:
        print("Pack first")
else:
    print("Add more")

example-2.py · A ticket, then an age limit

tickets = 1
age = 15
if tickets > 0:
    if age >= 17:
        print("Enjoy the film")
    else:
        print("An adult must come too")
else:
    print("Buy a ticket first")
print("Next customer")

Review

The inner if runs only when the outer test is true.
An else lines up with the if it belongs to.
Nested ifs can give each "no" its own answer, which one combined test can't. Next: values that count as true or false by themselves.

Practise this

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