hash arrays for basic Perl script

Question

I'm writing my first Perl script and am reading a small text file line by line. The fields are delimited by ':' so i want to split each field into a hash array using the first field(name) as the key for each. Also, (I think) I want a big hash that holds all the information, or maybe just an array that holds each field so I can print all info on one line based on a pattern. I've not gotten far as %info is creating odd # elements in the hash assignment. Should I make it a regular array, and am I even going about this the right way? Basically, lines are in this order.

name:phone:address:date:salary

#!/usr/bin/perl -w

use strict;

print $#ARGV;

if($#ARGV == -1)
{
    print "Script needs 1 argument please.\n";
    exit 1;
}

my $inFILE = $ARGV[0];

#open the file passed
open(IN, "$inFILE") || die "Cannot open: $!"; #open databook.txt

my %info = (my %name, my %phone, my %address, my %date, my %salary);
while(<IN>)
{
    %info = (split /:/)[1];


}

close($inFILE);

Logan Ding · Accepted Answer · 2013-11-06 06:35:47Z

4

First of all, you should define your data structure depending on how you would use the information parsed. If you're using the name as index to search the information, I suggest to use a nested hash, indexed by the name:

{name => {phone => ..., address => ..., date => ..., salary => ...}, ...}

If you're not going to use name as index, just store the information in an array:

[ {name => ..., address => ..., date => ..., salary => ...}, 
  {name => ..., address => ..., date => ..., salary => ...}, ...]

In most cases I would use the first one.

Secondly, arrays and hashes in Perl are flat. So this:

my %info = (my %name, my %phone, my %address, my %date, my %salary);

doesn't make sense. Use a ref to store the data.

Last but not least, Perl has a syntax sugar for the input file. Use <> to read file from arguments, instead of opening files explicitly. This makes the program more "Perlish".

use strict;
use warnings;
use Data::Dumper;

my $info = {};
while (<>) {
    chomp;
    my @items = split /:/, $_;
    $info->{$items[0]} = { phone => $items[1], 
                           address => $items[2], 
                           date => $items[3], 
                           salary => $items[4] };
}

print Dumper $info;

answered Nov 6, 2013 at 6:35

Logan Ding

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4 Comments

user2079828 Over a year ago

So, chomp off eol(forgot) store the delimited fields into an array called items, then store in a nested hash of hashes(wording?) with the key being the name '$items[0]. Does that sound correct?

Logan Ding Over a year ago

@user2079828 Yes that's what I meant.

user2079828 Over a year ago

Thank you, i'm just trying to understand exactly what is happening with the syntax. Still learning everything. Ok, this makes sense. I have been looking at a lot of code references, but could not seem to put anything coherent together. This should get me started, thank you.

Brad Gilbert Over a year ago

I would generally only use <> for short programs.

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