Like this?
$s = 'a b & & * * * * a * * * *& && & xy a';;
$s =~ s[(?<=\W)\s+(?=\W)][]g;;
print $s;;
a b &&**** a ****&&&& xy a
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.