use strict;
sub prepareFormat {
    my $format = shift();
    my ($i, @order) = 0;
    $format =~ s/([YMDhms]+)(\?)?/ $order[$i++] = substr($1,0,1); '('.
+('\d' x length($1))."$2)"/ge;
    $format = qr/^(?:$format)$/;
    return [$format, \@order];
}

sub parseDate {
    my ($format, $date) = @_;
    my @data = ($date =~ $format->[0])
        or return;
    my %result;
    for(my $i = 0; $i <= $#data; $i++) {
        $result{$format->[1]->[$i]} ||= $data[$i];
    }
    return map $result{$_}, qw(Y M D h m s);
}

#my $format = prepareFormat ('YYYY/MM/DD');
#my $format = prepareFormat ('YYYY-DD-MM|YYYY-DD-M|YYYY-D-MM|YYYY-D-M'
+);
#my $format = prepareFormat ('YYYY-DD?-MM?');
#my $format = prepareFormat ('YYYY-DD?-MM? hh?:mm?');
#my $format = prepareFormat ('YYYY-DD?-MM? hh?:mm?(?::ss?)?');
my $format = prepareFormat ('YYYY-DD?-MM?(?: hh?:mm?(?::ss?)?)?');

while (<>) {
    chomp;
    my ($year, $month, $day, $hour, $min, $sec) = parseDate($format, $
+_)
        or print "\tNot in the right format!\n" and next;
    print "Year: $year, Month: $month, Day: $day, Hour: $hour, Min: $m
+in, Sec: $sec\n";
}

[download]

The prepareFormat() returns a reference to an array containing the regexp and the mapping between the capturing parenthesis and the parts of the date, the parseDate() uses this structure to match the date and extract the data. It then returns (year,month,day,hour,min,sec).

As you can see from the examples you may accept&parse several different datetime formats at once.

Jenda
Always code as if the guy who ends up maintaining your code will be a violent psychopath who knows where you live.
   -- Rick Osborne

Edit by castaway: Closed small tag in signature

In reply to Re: date format string -> Reg Ex solution by Jenda
in thread date format string -> Reg Ex solution by markjugg

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