Firstly, grep is excessive. Since your keys are upper-case, simply use uc to upper-case things before matching.

#!/usr/bin/perl
use strict;
use warnings;

my @words;
while (<STDIN>) { push @words, split /\s/ }
my %wordscore = scrabble_score(@words);
for (sort keys %wordscore) {
    print qq/"$_" = $wordscore{$_} points\n/;
} 


sub scrabble_score {
    my %value = ( A => 1,  F => 4,  K => 5,  P => 3,   U => 1,  Z => 1
+0,
            B => 2,  G => 2,  L => 1,  Q => 10,  V => 4,
            C => 3,  H => 4,  M => 3,  R => 1,   W => 4,
            D => 2,  I => 1,  N => 1,  S => 1,   X => 8,
            E => 1,  J => 8,  O => 1,  T => 1,   Y => 4
    );
    
    my %score;
    for (@_) {
        my @letter = split "", uc $_;
        my $word = $_;
        $score{$word} = 0;
        for (@letter) { $score{$word}+=$value{$_} }
    }
    
    return %score;
}
[download]

Also, because of how hashes function, it will only print one instance of each word.

By the way, you aren't checking to make sure the word is possible in Scrabble: there are a limited quantity of each letter... :)

I found two problems:

You're printing $_, but $r contains what you want to print.

You should uppercase the input (using uc()). Hash lookups are case-sensitive.

I also have two recommendations:

It would make more sense if if ($word eq 'q'){ appeared before the split.

Something's really odd with your foreach+grep. In fact, there's no need for a foreach at all. Get rid of the foreach loops and use just @result = grep {defined $_} @pay{@word}; (which simplifies to @result = grep defined, @pay{@word};). You'd be smart if you went and reread some examples using grep, and make sure you know what @hash{list} returns.

Now you just have to sum up the elements of @result with something like my $sum = 0; $sum += $_ foreach @result;.

You could even remove the grep, replace it with a for/foreach loop that does both the validation and the summing. In fact, that's probably a good idea.

Here's how I'd do it:

my %scores = (
   map { $_ =>  1 } qw( A E I L N O R S T U ),
   map { $_ =>  2 } qw( B D G               ),
   map { $_ =>  3 } qw( C M P               ),
   map { $_ =>  4 } qw( F H V W Y           ),
   map { $_ =>  5 } qw( K                   ),
   map { $_ =>  8 } qw( J X                 ),
   map { $_ => 10 } qw( Q Z                 ),
);

print("Find the Scrabble value of a word.$/$/");

for (;;) {
   print("Enter a word (or just Enter to quit): ");
   local $_ = <STDIN>;
   last unless defined;
   chomp;
   last unless length;
   $_ = uc($_);

   my $sum = 0;
   $sum += $scores{$1} while (/([A-Z])/g);

   print("Scrabble value: $sum$/$/");
}
[download]

I was playing around with this and noticed a harmless but problematic side-effect of the way you construct the hash.

%scores = (
   map { $_ =>  1 } qw( A E I L N O R S T U ),
   map { $_ =>  2 } qw( B D G               ),
   map { $_ =>  3 } qw( C M P               ),
   map { $_ =>  4 } qw( F H V W Y           ),
   map { $_ =>  5 } qw( K                   ),
   map { $_ =>  8 } qw( J X                 ),
   map { $_ => 10 } qw( Q Z                 ),
);
print join($", sort keys %scores), $/;

__END__
10 2 3 4 5 8 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
[download]

Since you're filtering for letters, the numbers don't get picked up, but the maps are having a side-effect mapping of the other maps below them. Parens around the maps seems to fix it.

I also learned something from your example. I would have predicted that the last unless defined would not work right on empty input b/c $_ still contains a "\n" which would be defined. I would have been wrong.

I would have predicted that the last unless defined would not work right on empty input b/c $_ still contains a "\n"

It doesn't work on empty input. It works on eof/error. It's there to prevent the next two lines from giving "undefined value" warnings under use warnings. The last unless length that follows is what detects the empty string (since chomp removed the "\n" by then).

Wow, your %scores isn't defined correctly at all.

# perl -l
my %scores = (
   map { $_ =>  1 } qw( A E I L N O R S T U ),
   map { $_ =>  2 } qw( B D G               ),
   map { $_ =>  3 } qw( C M P               ),
   map { $_ =>  4 } qw( F H V W Y           ),
   map { $_ =>  5 } qw( K                   ),
   map { $_ =>  8 } qw( J X                 ),
   map { $_ => 10 } qw( Q Z                 ),
);
print "$_ => $scores{$_}" for keys %scores;
__END__
S => 1
T => 1
N => 1
K => 1
Y => 1
2 => 1
E => 1
Z => 1
J => 1
W => 1
B => 1
H => 1
D => 1
I => 1
10 => 1
G => 1
U => 1
F => 1
V => 1
Q => 1
M => 1
C => 1
L => 1
A => 1
O => 1
3 => 1
X => 1
P => 1
8 => 1
4 => 1
R => 1
5 => 1
[download]

Perhaps this is a good time for parentheses?

my %scores = (
   map( { $_ =>  1 } qw( A E I L N O R S T U ) ),
   map( { $_ =>  2 } qw( B D G               ) ),
   map( { $_ =>  3 } qw( C M P               ) ),
   map( { $_ =>  4 } qw( F H V W Y           ) ),
   map( { $_ =>  5 } qw( K                   ) ),
   map( { $_ =>  8 } qw( J X                 ) ),
   map( { $_ => 10 } qw( Q Z                 ) ),
);
print "$_ => $scores{$_}" for keys %scores;
__END__
[download]

You can find it here .

Good luck!

This would be a great place to use List::Util's sum: use map to turn an array of characters into an array of points values, then add it all up.

use strict;
use warnings;
my %pay = ( A => 1,  F => 4,  K => 5,  P => 3,   U => 1,  Z => 10,
            B => 2,  G => 2,  L => 1,  Q => 10,  V => 4,
            C => 3,  H => 4,  M => 3,  R => 1,   W => 4,
            D => 2,  I => 1,  N => 1,  S => 1,   X => 8,
            E => 1,  J => 8,  O => 1,  T => 1,   Y => 4
);

my $word;
my @word;
print "Enter word to calculate.\n";
print "\nPress 'q' to quit\n";

while (){
    my $total_points = 0;
    print "\nWord: ";
    chomp ($word = uc(<STDIN>));
    die "Quiting program...\n" if ($word eq 'Q');
    foreach my $letter (split("", $word)){
        $total_points +=  $pay{"$letter"} if defined $pay{"$letter"} ;
        printf "Letter \"%s\" = %d points. Total points: %d\n", $lette
+r,$pay{"$letter"}, $total_points;
    }
}
[download]

Enter word to calculate.

Press 'q' to quit

Word: test
Letter "T" = 1 points. Total points: 1
Letter "E" = 1 points. Total points: 2
Letter "S" = 1 points. Total points: 3
Letter "T" = 1 points. Total points: 4

Word: q
Quiting program...
[download]