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Conditions and loops

if / elsif / unless, for over a list or range, while, statement modifiers, and next / last.

Runs in Zerethon IDE · Perl 5.40 Official Perl documentation ↗
main.pl 
use v5.40;

for my $n (1 .. 5) {
    if ($n % 2 == 0) {
        say "$n even";
    } elsif ($n == 5) {
        say "$n last";
    } else {
        say "$n odd";
    }
}

my $i = 3;
while ($i > 0) {
    $i--;
    next if $i == 1;
    say "i = $i";
}

my @fruits = ("apple", "pear");
for my $index (0 .. $#fruits) {
    say "$index $fruits[$index]";
}

my $temperature = -2;
say "freezing" unless $temperature > 0;

Output

1 odd
2 even
3 odd
4 even
5 last
i = 2
i = 0
0 apple
1 pear
freezing
  • The braces are always required, even for one statement; or put the condition after it: say "x" if $ok;.
  • next skips to the next round of a loop and last leaves it (Perl's continue and break).
  • False values are 0, "0", "" and undef; everything else is true.
  • for my $item (@list) gives each element; inside a loop without a named variable the element is $_.

Related topics

Official references