Name,Type,Age
Lily,Cat,4
Buster,Dog,5
Tweety,Bird,2

##</code><code>##

use strict;
use warnings;
use Text::CSV;

use subs qw(hlookup);

print "The animal in line 2 is ", hlookup("some_csv.csv", "Age", 2), " years old.\n";
print "The critter in line 4 is called ", hlookup("some_csv.csv", "Name", 4), ".\n";

sub hlookup {
     my $csv_file = shift;
     my $field_name = shift;
     my $row_num = shift;

     my $csv = Text::CSV->new ( { binary => 1 } )  # should set binary attribute.
                 or die "Cannot use CSV: ".Text::CSV->error_diag ();
 
     open my $fh, "<:encoding(utf8)", $csv_file or die "test.csv: $!";

     my $field_num;
     my $first_row = $csv->getline( $fh );

     my @result;
     for (my $idx = 0; $idx <= @$first_row; $idx++) {
         if ($first_row->[$idx] eq $field_name) {
             $field_num = $idx;
             push @result, $first_row->[$field_num];
             last;
         }
     }
     die "Field name '$field_name' not found on the first row of $csv_file" if not defined $field_num;

     while ( my $row = $csv->getline( $fh )) {
         push @result, $row->[$field_num];
     }
    
     $csv->eof or $csv->error_diag();
     close $fh;

     return $result[$row_num - 1];  # -1 since array indexes are 0-based,
                                    # and we count our lines 1-based
}

##</code><code>##

use strict;
use warnings;
use Text::CSV;

use subs qw(hlookup);

print "The animal in line 2 is ", hlookup("some_csv.csv", "Age", 2), " years old.\n";
print "The critter in line 4 is called ", hlookup("some_csv.csv", "Name", 4), ".\n";

sub hlookup {
     my $csv_file = shift;
     my $field_name = shift;
     my $row_num = shift;

     my $csv = Text::CSV->new ( { binary => 1 } )  # should set binary attribute.
                 or die "Cannot use CSV: ".Text::CSV->error_diag ();
 
     open my $fh, "<:encoding(utf8)", $csv_file or die "test.csv: $!";

     my $field_num;
     my $first_row = $csv->getline( $fh );
     $csv->column_names(@$first_row);

     my $all =  $csv->getline_hr_all($fh, $row_num - 2, 1);
                            # - 2 since array indexes are 0-based,
                            # and we count our lines 1-based,
                            # and because we've already read the first
                            # line.

    return $all->[0]->{$field_name}
}

##</code><code>##

The animal in line 2 is 4 years old.
The critter in line 4 is called Tweety.