I, too, may not really understand your question, but:

c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le
"my @array = qw(A R N D);
 dd \@array;
 ;;
 @array = 'B N M C' =~ m{ \S }xmsg;
 dd \@array;
 ;;
 @array = 'Be No More Care' =~ m{ \S }xmsg;
 dd \@array;
 ;;
 @array = 'Be No More Care' =~ m{ [[:upper:]] }xmsg;
 dd \@array;
 ;;
 @array = 'Be No More Care' =~ m{ \S+ }xmsg;
 dd \@array;
"
["A", "R", "N", "D"]

["B", "N", "M", "C"]

["B", "e", "N", "o", "M", "o", "r", "e", "C", "a", "r", "e"]

["B", "N", "M", "C"]

["Be", "No", "More", "Care"]
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Note that the pattern you use is really important!