Question

I have a data like this:

Re: Building A

Month
kWh
1
100
2
110
3
105


Re: Building B

Month
kWh
1
200
2
210
3
205

I would like to convert it to multiple text files one for each building. My plan is to:

1. extract the values between the building delimiter line
2. convert the lines into a table

For task (1) I tried to use the flip-flop operator like this:

while( <DATA> ) {
  next unless /^Re: Building A/ .. /^Re: Building B/;
  my $line = $_;
  print $line;
}

But it does not work because the above will show only the data for building A. The data is for multiple buildings (about 50 of them) so that I need to do this somewhat recursively. I have not started to do task (2).

Any help will be appreciated.

Answer 1

I would do something like this:

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

my %buildings;

while (<DATA>) {
    chomp;
    $buildings{$1} = [] if /^Re: Building ([AB])/;
    push @{$buildings{$1}}, $_ if $_;
}

while (my ($building, $data) = each %buildings) {
    open(my $out, '>', "$building.txt") or die "Unable to open file for writing: $!\n";

    for my $i (1 .. $#$data / 2) {
        print $out sprintf "%s\t%s\n", $data->[$i*2-1], $data->[$i*2];
    }
    close $out;
}

A.txt:

Month   kWh
1       100
2       110
3       105

B.txt:

Month   kWh
1       200
2       210
3       205