Search for hash in an array by value

By : kost
Source: Stackoverflow.com
Question!

I have a function which extracts Excel data into an array of hashes like so:


sub set_exceldata {

    my $excel_file_or = '.\Excel\ORDERS.csv';
    if (-e $excel_file_or) {

        open (EXCEL_OR, $excel_file_or) || die("\n can't open $excel_file_or: $!\n");                   
        while () {

            chomp;
            my ( $id, $date, $product, $batchid, $address, $cost ) = split ",";
            my %a = ( id      => $id
                    , date    => $date
                    , product => $product
                    , batchid => $batchid
                    , address => $address
                    , cost    => $cost
                    );
            push ( @array_data_or, \%a );
        }
        close EXCEL_OR;
    }
}

Populating the array of hashes is fine. However, the difficult part is searching for a particular item (hash) in the array. I can't seem to locate items that might have an id or 21, or a batchid of 15, or a cost > $20 etc.

How would I go about implementing such a search facility?

Thanks to all,

By : kost


Answers

With the power of grep

my @matching_items = grep {
  $_->{id} == 21
} @array_data_or;

If you know there will be only one item returned you can just do this:

my ($item) = grep {
  $_->{id} == 21
} @array_data_or;

(Untested, and I haven't written one of these in a while, but this should work)

By : Quentin


If you're sure that the search always returns only one occurence or if you're interested in only the first match then you could use the 'first' subroutine found in List::Util

use List::Util;

my %matching_hash = %{ first { $_->{id} == 21 } @array_data_or };

I enclosed the subroutine call in the %{ } block to ensure that the RHS evaluates to a hash.

By : aks


Something like log4Net? or a messaging queue system, sks MSMQ



This video can help you solving your question :)
By: admin