Question

I’m trying to join an array this way:

@cols = (1,2,3,4); 
my $s = join("|$_", @cols);
print $s;

and I expect the following output:

1|2|3|4    

but that doesn’t work.

I was also looking for some reduce-like function but I can’t find one nor I know how to write one in Perl.

Using CPAN is not an option as this program will be executed in computers I cannot install anything else.

What other similar function can I use for that purpose?
How can I write that generalized join or reduce function in Perl?

Thanks.

Answer 1

I suspect you want:

my $s = join('|', @$hr{@cols} );

With reduce:

use List::Util 'reduce';
my $s = reduce { "$a|$hr->{$b}" } '', @cols;

(though that produces a leading |).