Yes and no. With map, it depends on the pattern.

>perl -le"@rxs='(.)(.)'; $line = 'ab'; my $cnt = grep $line =~ $_, @rx
+s; print $cnt"
1

>perl -le"@rxs='(.)(.)'; $line = 'ab'; my $cnt = map $line =~ $_, @rxs
+; print $cnt"
2
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grep is more robust. It'll work with just about any expression, whereas map only works with very specific expressions.