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perl

perl combine map and each

I was just wondering if this is posssible:

use Modern::Perl;

my @list = ('a' .. 'j');

map { func($_) } each(@list);

sub func {
  my ($index, $value) = @_;
  say "$index => $value";
}
Solution

  • No you can't, because each returns a key/value pair each time it is called. You are calling it just once, so it will pass (0, $list[0]) to the map, and the subroutine will be called once for each value.

    If you want to call func with each key/value pair you can write

    map { func($_, $list[$_]) } keys @list;

    but that is misusing map because it is meant for mapping one list to another. You should use for instead like this

    func($_, $list[$_]) for keys @list;

    You could also use each like this

    my ($i, $v);
func($i, $v) while ($i, $v) = each @list;