sub getCorpus {                
my %corpus;                    
my $text;                    
 opendir (DR, "$_[0]") || die ("Cannot open directory");  
my @files = readdir(DR);
 for my $i (0 .. $#files) {            
 if ($files[$i] =~ /\.txt/ && $files[$i] !~ /\._/) {    
 {
local $/ = undef ;                            
 open(FILE, "$_[0]/$files[$i]") or die ("file not found");
 $text = <FILE> ;    
}
 $files[$i] =~ s{\.txt}{};
 $corpus{$files[$i]} = $text; 
}
}
return %corpus;                    #Returns a hash called corpus
}

my %mycorpus = (
    a => "date:#20180101# title:#cat dog# text:#sheep sheep sheep shee
+p#" ,

    b => "date:#20180101# comment:#woof woof#",

    c => "date:#20180101# title:#cow puppy# text:#pig pig pig#",
);



my %counts;
foreach my $filename (sort keys %mycorpus) {
        my $date;
        my $dataset = '';

                
        while ($mycorpus{$filename} =~ /date:#(\d{8})#/g){ 
            $date = $1; 
        }
            
         while ($mycorpus{$filename} =~ /title:#(.*?)#/g){
            $dataset = $1;
                    #Actions usually performed here which clean the ti
+tles (i.e. substituting certain characters)
                                                }    
                                                
         while ($mycorpus{$filename} =~ /text:#(.*?)#/g){
            $dataset = $1;
            #Actions usually performed here which clean the text
                    
                                                }
                                                                      
+          
          while ($mycorpus{$filename} =~ /comment:#(.*?)#/g){
                $dataset = $1;
                    #Actions usually performed here which clean the co
+mments    
                                                 }    
            
            my @words = split /\W+/, $dataset;
            
            foreach my $word (@words){
                
                if ($word =~ /(\w+)/gi){
                    $word =~ tr/A-Z/a-z/;
                    $counts{$date}{$word}++;
                    $word_types{$word}++;
                    $overallcounts{$date}++;
                }
            }   
        }

 use Data::Dumper;
 print Dumper \%counts;
[download]

The output I was expecting was:

$VAR1 = {
          '20180101' => {
                          'puppy' => 1
                          'dog' => 1
                          'cat' => 1
                          'cow' => 1
                          'sheep' => 4,
                          'woof' => 2,
                          'pig' => 3
                        }
        };
[download]

But in reality I got:

$VAR1 = {
          '20180101' => {
                          'sheep' => 4,
                          'woof' => 2,
                          'pig' => 3
                        }
        };
[download]

Does it seem like I am doing something wrong here, or is this a recognised way that while loops work? In the instance of the latter, is there any way to work around this? Thanks!