Question

I want to see if I have repeated items in my array, there are over 16.000 so will automate it
There may be other ways but I started with this and, well, would like to finish it unless there is a straightforward command. What I am doing is shifting and pushing from one array into another and this way, check the destination array to see if it is “in array” (like there is such a command in PHP).

So, I got this sub routine and it works with literals, but it doesn’t with variables. It is because of the ‘eq’ or whatever I should need. The ‘sourcefile’ will contain one or more of the words of the destination array.

// Here I just fetch my file


    $listamails = <STDIN>;
    # Remove the newlines filename
    chomp $listamails;
    # open the file, or exit
    unless ( open(MAILS, $listamails) ) {

    print "Cannot open file \"$listamails\"\n\n";
    exit;
    }
    # Read the list of mails from the file, and store it
    # into the array variable @sourcefile
    @sourcefile = <MAILS>;
    # Close the handle - we've read all the data into @sourcefile now.
    close MAILS;


    my @destination = ('hi', 'bye');

    sub in_array
    {
       my ($destination,$search_for) = @_;
       return grep {$search_for eq $_} @$destination;
    }

    for($i = 0; $i <=100; $i ++)

    {
      $elemento = shift @sourcefile;
      if(in_array(\@destination, $elemento))
      {
        print  "it is";
      }
      else
      {
        print "it aint there";
      }
    }

Well, if instead of including the $elemento in there I put a ‘hi’ it does work and also I have printed the value of $elemento which is also ‘hi’, but when I put the variable, it does not work, and that is because of the ‘eq’, but I don’t know what else to put. If I put == it complains that ‘hi’ is not a numeric value.

Answer 1

By the way, when looking for duplicates in a large number of items, it’s much faster to use a strategy based on sorting. After sorting the items, all duplicates will be right next to each other, so to tell if something is a duplicate, all you have to do is compare it with the previous one:

@sorted = sort @sourcefile;
for (my $i = 1; $i < @sorted; ++$i) {   # Start at 1 because we'll check the previous one
    print "$sorted[$i] is a duplicate!\n" if $sorted[$i] eq $sorted[$i - 1];
}

This will print multiple dupe messages if there are multiple dupes, but you can clean it up.