@my_array_2 = map { local $_ = $_; s/^CHOP_ME_OFF_//; $_ } @my_array;

##</code><code>##

@my_array_2 = map {s/^CHOP_ME_OFF_//; $_ } @my_array;

##</code><code>##

@my_array = map {s/^CHOP_ME_OFF_//; $_ } @my_array;