Perl hash example

Perl: hash example

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An example of using a hash in Perl and sorting over its values.

Please download The Raven for this example. Save this file somewhere on your hard disk.

Start Komodo, then copy the code below and save it. Then run the code. In the Debugging Options window, enter the path and filename to TheRaven.txt into the filed for Script Arguments. This line contains what you would normally type on the commandline, i.e. the arguments taht get stored in the global variable @ARGV (the argument vector).

 #!/usr/bin/perl
use strict;
use warnings;
 
my $filename = shift(@ARGV);
my @tokens;
my %dictionary;
 
open (INFILE,"< $filename") or die("Failed to open $filename: $!");
 
while (my $line = <INFILE>) {
    $line = lc($line);
    $line =~ s/^[^a-z]+//;
    @tokens = split(/[^a-z]+/,$line);
    foreach my $word (@tokens) {
        $dictionary{$word}++;
    }
}

close(INFILE);

my @keys = keys(%dictionary);
my @value_sorted_keys = sort {$dictionary{$a}<=>$dictionary{$b}} (@keys);
foreach my $word (@value_sorted_keys) {
   print "$dictionary{$word} $word\n";
}
 
exit();

Analyse this code line by line.

   

Further reading and resources