Parse fixed-width files

Question

I have a lot of text files with fixed-width fields:

            
Dave    Thomas    123 Main
Dan     Anderson  456 Center
Wilma   R         


        

Answer 1

As user604939 mentions, unpack is the tool to use for fixed width fields. However, unpack needs to be passed a template to work with. Since you say your fields can change width, the solution is to build this template from the first line of your file:

my @template = map {'A'.length}        # convert each to 'A##'
                =~ /(\S+\s*)/g;  # split first line into segments
$template[-1] = 'A*';                  # set the last segment to be slurpy

my $template = "@template";
print "template: $template\n";

my @data;
while () {
    push @data, [unpack $template, $_]
}

use Data::Dumper;

print Dumper \@data;

__DATA__
            
Dave    Thomas    123 Main
Dan     Anderson  456 Center
Wilma   Rainbow   789 Street

which prints:

template: A8 A10 A*
$VAR1 = [
          [
            'Dave',
            'Thomas',
            '123 Main'
          ],
          [
            'Dan',
            'Anderson',
            '456 Center'
          ],
          [
            'Wilma',
            'Rainbow',
            '789 Street'
          ]
        ];