Question

I have CSV file which has timestamp in the first column as shown below sample:

Time,head1,head2,...head3
00:00:00,24,22,...,n
00:00:01,34,55,...,n
and so on...

I want to filter out the data with specific time range like from 11:00:00 to 16:00:00 with the header and put into an array. I have written the below code to get the header in an array.

#!/usr/bin/perl -w
use strict;

my $start = $ARGV[0];
my $end = $ARGV[1];

my $line;
$line =<STDIN>;
my $header = [ split /[,\n]/, $line ];

I need help on how to filter data from file with selected time range and create an array of that.

Answer 1

I kind of cheated. A proper program would probably use DateTime and then compare with DateTime’s compare function. If you’re only expecting input in this format, my “cheat” should work.

#!/usr/bin/perl
use strict;
use warnings;

use Text::CSV;
use DateTime;

my $start = 110000;
my $end   = 160000;

my $csv = Text::CSV->new () or die "Cannot use CSV: ".Text::CSV->error_diag ();

my @lines;
open my $fh, "<:encoding(utf8)", "file.csv" or die "Error opening file: $!";
while ( my $row = $csv->getline( $fh ) ) {
    my $time = $row->[0];
    $time =~ s/\://g;
    if ($time >= $start and $time <= $end) {
        push @lines, $row;
    }
}
$csv->eof or $csv->error_diag();
close $fh;

#do something here with @lines