I've been trying to teach myself hashes and have come up with the following block of code to change a line in a pipe-deliminated flat file. I was wondering if my fellow monks here could give me some advice as to how I could make this code simpler more efficient etc. I'm also wondering if there are better ways to do the same function. All suggestions, comments, etc. would be appreciated! Thanks!
Stamp_Guy 
#!/usr/bin/perl -w
use strict;

# Predeclare variables.
my %test;
my @fileData;
my @sorted;

# Initialize the variable that will hold the data to be changed.
my $change = "this is cool";

# Open the file
open(TEST, "test.txt") || die "File couldn't be opened for reading: $!
+";

# Create a hash
while (<TEST>) {
my ($key,@fileData) = split /\|/;
chomp @fileData;
$test{$key} = \@fileData;
}

# Change the data
$test{mykey}->[1] = "$change";

# Place all the hash data into an array of pipe-seperated values for s
+orting.
foreach my $key (keys %test) {
    push (@sorted, "$key|$test{$key}->[0]|$test{$key}->[1]|$test{$key}
+->[2]|$test{$key}->[3]");
}

# Sort the data by the number in the last part of the array.
@sorted = map $_->[1],
    sort { $a->[0] <=> $b->[0] }
        map [ substr($_,rindex($_,'|')+1), $_ ],
        @sorted;

# Put the line breaks back in.
for (@sorted) {
$_ = "$_\n";
}

open(TEST, ">test.txt") || die "File couldn't be opened for writing: $
+!";
print TEST @sorted;
close(TEST)

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In reply to Learning to use the hash effectively by Stamp_Guy

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