Course of Raku / Essentials / Conditional checks

Ternary operator

The ternary operator in Raku is a two-part construction ?? … !!. A Boolean test is followed by two expressions, one of which is executed depending on the result of the test.

my $shines = 'Sun';
my $day-time = $shines eq 'Sun' ?? 'day' !! 'night';
say $day-time;

With the current value of the $shines variable, this program prints day. If you change it to Moon, the result will be night.

It is possible to chain ternary expressions. Just make sure it doesn’t get too complicated.

my $hours = 20;
my $day-time =
    $hours <= 6 ?? 'Night' !!
    $hours <= 12 ?? 'Morning' !! 
    $hours <= 18 ?? 'Afternoon' !! 'Evening';
say $day-time;

Here, depending on the value in $hours, a different part of day will be reported.

Practice

Complete the quiz that covers the contents of this topic.

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