my $str = "foobarbaz";
my @a = $str =~ /(.)oo(.)ar(.)az/;
local $, = ", ";
print @a;

__OUTPUT__
f, b, b

##</code><code>##

my $regex = qr/(.)oo(.)ar(.)az/;
my $str = "foobarbaz";
my @a = $str =~ $regex;
$str =~ s/$regex/$3$2$1/;
local $, = ", ";
print $str, @a;

__OUTPUT__
bbf, f, b, b