Jabox has asked for the wisdom of the Perl Monks concerning the following question:

Hello Everyone,

Not sure how to name the title so sorry if it didn't make sense.

So I am still practicing/studying by making fun pointless codes so I can get use to Perl *first language* and I got curious on how to replace the long conditional statement. Of course I had some help, now I want to add a conditional statement to that shortcut but I don't know how...

Here is the snippet

sub menu {
        foreach my $keys (keys(%hash)) {
                my $num = 1;
                foreach my $race (@{$hash{$keys}}) {
                        print "$num . $race\n";
                        $num++;
                }
                print "\nGive me your choice..\n";
                $choice = ucfirst(<STDIN>);
                chomp $choice;
                $choice--;

                my $sub = "$hash{$keys}[$choice]" . "choice";

                print "You have chose " .  $hash{$keys}[$choice] . "!\
+n";
                &{$sub}();
        }
}

[download]

I want to make something to where the numbers AND the STDIN work, only the number works. Say if tomato was the first key, I put 1 and it would work but I also want to make it where if they put in tomato it will also work. Instead if I put in any random answer, it always goes to the last key.

I was curious and I tried putting something like

 if ($choice eq $hash{keys}) {}

But of course it didn't work.. I want to do this because then I can put

 else { print "Please put in a valid answer\n"; &menu;}

And also accept the full "tomato" input than just the key "1"

I'm still in the beginning stage of learning and I got curious.. Thank you in advance! And I apologize if I didn't explain it well...

ALSO, the &{$sub}(); doesn't work with use strict;, is there a way to do this with strict?

.

Replies are listed 'Best First'.
Re: how to add conditionals to hash and stdin.
by choroba (Cardinal) on Mar 13, 2014 at 15:42 UTC
    You are after a dispatch table. 
    #!/usr/bin/perl
use warnings;
use strict;

my @actions = qw( add subtract quit );
my %dispatch = (
                 add => sub {
                     my ($x, $y) = map int rand 10, 1, 2;
                     print "$x + $y = ", $x + $y, "\n";
                 },
                 subtract => sub {
                     my ($x, $y) = map int rand 10, 1, 2;
                     print "$x - $y = ", $x - $y, "\n";
                 },
                 quit => sub { exit },
               );

while (1) {
    for my $idx (0 .. $#actions) {
        print "$idx) $actions[$idx]\n";
    }

    chomp(my $choice = <>);

    $choice = $actions[$choice] if $choice =~ /^[0-9]$/;
    if (exists $dispatch{$choice}) {
        $dispatch{$choice}->();
        next
    }

    print "Invalid option.\n";
}

    [download]
    لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ
[reply]
[d/l]
Re: how to add conditionals to hash and stdin.
by NetWallah (Canon) on Mar 13, 2014 at 16:01 UTC
    Some of your code can be re-written for improved readability, and more perl-like: 
           foreach my $keys (keys(%hash)) {
                my $races = $hash{$keys}; # For easy access to @$races
+ ...
                my $choice = "INVALID";
                while (not ( $choice=~/^\d+$/ and defined  $races->[$c
+hoice -1])){
                   print ($_ +1) . " . " . $races->[$_] . "\n" for 0..
+$#$races;

                   print "\nGive me your choice..\n";
                   chomp ( $choice = <STDIN>); 
                }
               ....

    [download]
    **UNTESTED **

            What is the sound of Perl? Is it not the sound of a wall that people have stopped banging their heads against?
                  -Larry Wall, 1992

[reply]
[d/l]

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