Perl substr error - perl

Question

I have problem with Perl substr function. It is so simple, but anyway... Don't know what is the problem.
sub encode_date
{
$date = $_[0];
$day = substr($date, 0, 2);
$month = substr($date, 2, 2);
$year = substr($date, 6, 4);
return "$year-$month-$day";
}
Sub accept "DD.MM.YYYY" formatted string and have to convert it to "YYYY-MM-DD" format.
Input : 09.09.1993
Output : 0-09-93-19 ???
Can anybody explain what's wrong, please.
p.s.: I wrote another sub for decoding date (from 'yyyy-mm-dd' to 'dd.mm.yyyy') and all work properly.
sub decode_date
{
$date = $_[0];
$year = substr $date, 0, 4;
$month = substr $date, 5, 2;
$day = substr $date, 8, 2;
return $day.".".$month.".".$year;
}
Sure, I tried both substr $date, 0, 2; and substr($date, 0, 2); and different combinations of the return value.

Answer 1

Month starts at index 3, not 2.
sub encode_date
{
my ($date) = #_;
my $day = substr($date, 0, 2);
my $month = substr($date, 3, 2);
my $year = substr($date, 6, 4);
return "$year-$month-$day";
}
Perhaps better way would be splitting string by non-digit(.), reverse numbers, and join them with dash -
sub encode_date
{
my ($date) = #_;
return join "-", reverse split /\D/, $date;
}

Answer 2

Your problem is that your offsets are wrong, because they don't take into account the separators. (For example, the month starts at offset 3, not 2, because it comes after the two-character date plus a period.)
That said, I think the best way to write this function is:
sub encode_date($) {
if ($_[0] =~ /^(\d\d)\.(\d\d)\.(\d{4})$/) {
return "$3-$2-$1";
}
}

Answer 3

sub encode_date
{
$date = $_[0];
$day = substr($date, 0, 2);
$month = substr($date, 3, 2);
$year = substr($date, 6, 4);
return "$year-$month-$day";
}
There were 2 problems. I used encode_date(encode_date($date)); (2 times)Another was $month = substr($date, 2, 2); Correct is $month = substr($date, 3, 2);