Instead of a filter, you might want to change every item in a list. For example, suppose you have a list of numbers that should be formatted as “money numbers” for output, as with the subroutine &big_money from Chapter 13. You don’t want to modify the original data; you need a modified copy of the list just for output. Here’s one way to do that:

my @data = (4.75, 1.5, 2, 1234, 6.9456, 12345678.9, 29.95);
my @formatted_data;

foreach (@data) {
  push @formatted_data, &big_money($_);
}

That looks similar in form to the example code used at the beginning of the previous section on grep, doesn’t it? So it may not surprise you that the replacement code resembles the first grep example: