karls-mac-mini:monks karl$ perl -MData::Dump  -E 'dd split /[^a]/, qq(dftaatzaaadfaa)';
("", "", "", "aa", "", "aaa", "", "aa")

karls-mac-mini:monks karl$ perl -E 'say scalar grep {$_ eq 'aa'} split /[^a]/, qq(dftaatzaaadfaa)';
2

karls-mac-mini:monks karl$ perl -E 'say scalar grep {/aa/} split /[^a]/, qq(dftaatzaaadfaa)';
3