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my $value;
my @list = (1, 2, 3);

for $value (@list) {
  if ($value % 2 == 0) {
    last;
  }
}

print "$value is even\n";

However, the loop treats the iteration variable $value as local. So when it exits the list, $value regains the value it had before the loop. Since it was uninitialized before the loop, it therefore remains undefined afterwards, and the final print statement prints {{ is even}}.

Compliant Solution (Expanded

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Loop)

This compliant solution correctly prints 2 is even. It accomplishes this by moving the print statement inside the loop, and therefore never refers to $value outside the loop.

my @list = (1, 2, 3);

for my $value (@list) {
  if ($value % 2 == 0) {
    print "$value is even\n";
    last;
  }
}

Compliant Solution (

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External Variable)

This compliant solution preserves the value of $value by assigning it to a lexical variable defined outside the loop. It still declares $v to be private to the loop using my.

my @list = (1, 2, 3);

my $value;
for my $v (@list) {
  if ($v % 2 == 0) {
    $value = $v;
    last;
  }
}

print "$value is still even\n";

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my @list = (1, 2, 3);

for ($value = 1; $value < 4; $value++) {
  if ($value % 2 == 0) {
    last;
  }
}

print "$value is still even\n";

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