Re: need regular expression

[ioannis]

in reply to need regular expression

for ( my @dates = qw( 4-10-31 14-11-31 ) ) {
        s/
        ^
        (\d)
        (\d)?
        (-\d{1,2}-\d{1,2})
        $
        /($2?"20$1":"200").$1.$+/ex
        and print;
}

[ioannis]

This formula is simpler than the one earlier. The main insight here is to avoid strings; it is better to use arithmetic addition to construct the 'year' string (i.e. 20xx) .

for ( my @dates = qw( 4-10-31 14-11-31 ) ) {
        s/
        ^
        (\d{1,2})
        ((?:-\d{1,2}){2})
        $
        /(2000+$1).$+/xe
        and print;
}

[Perl Mouse]

I prefer to use strings - in that case, it becomes easy to deal with 3 or 4 digit years as well:

    my @dates = qw /4-10-31 14-11-31 1979-10-10/;
    for (@dates) {
        s/(\d+)/substr("2000", 0, -length($1)).$1/e;
        print "$_\n";
    }
    __END__
    2004-10-31
    2014-11-31
    1979-10-10