Re: Search and replace regex, but only retain a portion of the string

Using two substitutions is cleaner:

    $dest =~ s/\W+\[MSRN\]|\W+/_/g;
    $dest =~ s/_$//;
[download]

i.e. replace sequences of non-word characters by underscores, then remove the last underscore.

I can't think of a non-hackish solution with one substitution only.

    $dest =~ s/(?:\W+(?:MSRN\])?|\W+)(?(?=$)(?{$%=1})|(?{$%=0}))/$%?''
+:'_'/ge;
[download]

map{substr$_->[0],$_->[1]||0,1}[\*||{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^*ARGV,3]