[Oc-pm] looking for a bit of of help using "tr" & while loo

[Ben Tilly]

On Mon, Aug 25, 2008 at 2:09 AM, Raul Ruiz Jr. <fast.linux at yahoo.com> wrote:
> I made a card shuffling program for a school project. It works! I was very
> happy about that :)
>
> However, I'm trying to figure out a way to convert my abbreviated Cards
> (located in @startingdeck) to actual words using a shortcut. I'm trying to
> use "tr" to convert my letters: For example; H now becomes Hearts, or K now
> is displayed as KING and so on. Here is my shuffle code. Can someone help me
> with how I can approach this in my program. I'm trying to use a while loop
> and  "tr" to translate the Letters to actual words. I used the following
> loop thats high lighted in blue, and this is not doing what I want:
> Thanks for everyones time.

Unfortunately tr only substitutes letter for letter, so it cannot
change the number of letters.  You want to use regular expressions and
the s operator.  Like this (untested):

  for my $card (@startingdeck) {
    $card =~ s/A/Ace/;
    $card =~ s/K/King/;
    $card =~ s/Q/Queen/;
    $card =~ s/J/Jack/;

    $card =~ s/D/Diamond/;
    $card =~ s/H/Heart/;
    $card =~ s/S/Spade/;
    $card =~ s/C/Club/;
  }

Note that I used mixed case so that, for instance A didn't turn into
ACE which would later turn into ACLUBE when the C was substituted.  If
you wish to change that you can then uc all of the cards or else use
the following trick:

  my %expanded = (
    A => "ACE",
    K => "KING",
    Q => "QUEEN",
    J => "JACK"

    D => "DIAMOND",
    H => "HEART",
    S => "SPADE",
    C => "CLUB",
  );

  # This line assumes no metacharacters, and no key is a piece of another.
  my $re = join "|", keys %expanded;
  # If those assumptions are wrong, use this version instead:
  # my $re = join "|", map quotemeta($_), reverse sort keys %expanded;

  for my $card (@startingdeck) {
    $card =~ s/$re/$expanded{$1}/g;
  }

However note that it is simplest to just start the starting deck off
with what you want:

  my @startingdeck;
  for my $size ("ACE", 2..10, "JACK", "QUEEN", "KING") {
    for my $suit ("HEART", "DIAMOND", "CLUB", "SPADE") {
      push @startingdeck, "$size $suit";
    }
  }

And while I'm giving general advice, use strict.  See
http://www.perlmonks.org/index.pl?node=strict.pm for an explanation
why.

Cheers,
Ben