the reverse call inside map is called in list context so it reverses the list formed by its arguments ($_). Call it inside scalar to obtain the desired behavior: 
perl -le '$,=":";print map {scalar(reverse $_)} split( /\./, (reverse 
+"filename.ext"), 2)'

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In reply to Re: elements not reversing inside a map by salva
in thread elements not reversing inside a map by Transient

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