$s = '1-5,6a-e,7,10-13';
@s = split ( ',', $s );
for (@s) {
    if (/(\d+)-(\d+)/) {
      $tmp = '';
        for ( $1 .. $2 ) {
            $tmp .= "$_ ";
        }
        $_ = $tmp;
    }
}
print "@s";

# 1 2 3 4 5  6a-e 7 10 11 12 13 

##</code><code>##

($_='kkvvttuubbooppuuiiffssqqffssmmiibbddllffss')
 =~y~b-v~a-z~s;                             print