Re: Re: help with algorithm

OK, this seems to almost work; I want to make sure I'm using this correctly; I'm trying:

#!/usr/bin/perl

$test = 12;
print "Days mask is $test.\n";
our %daycode = (
               Sunday     =>  1,
               Monday     =>  2,
               Tuesday    =>  4,
               Wednesday  =>  8,
               Thursday   => 16,
               Friday     => 32,
               Saturday   => 64,
              );

our %codeday;
@codeday{ values(%daycode)} = keys %daycode;

sub days {
    my $mask = shift || 127;
    sort { $daycode{$a} <=> $daycode{$b} }
        grep { $mask & $daycode{$_} }
            keys %daycode;
}

@newtest = days($test);

foreach $num (@newtest) {
print "$newtest[$num]\n";
}
[download]

If I try 1 value for $test, like 4, it accurately returns Tuesday. However, if I use a complex value, like say 12, it returns Tuesday, Tuesday (where it should be Tuesday, Wednesday).

Am I doing something wrong in interpreting this?

Comment on Re: Re: help with algorithm Download Code

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Re: Re: Re: help with algorithm by sauoq (Abbot) on Nov 17, 2002 at 01:44 UTC
That code is working fine. You just make an error in the way you check the returned values. `@newtest = days($test); foreach $num (@newtest) { print "$newtest[$num]\n"; }` [download] The array, `@newtest`, is assigned `('Tuesday', 'Wednesday')` as expected but you iterate over it and use each element as an index back into `@newtest`. You are printing `$newtest['Tuesday']` and `$newtest['Wednesday']` but both `'Tuesday'` and `'Wednesday'` evaluate to 0 in numerical context. So, You print `$newtest[0]` twice and `$newtest[0]` holds `'Tuesday'`. That's why you print `'Tuesday'` twice. Try writing that loop as: `foreach $day (@newtest) { print $day,"\n"; }` [download] -sauoq "My two cents aren't worth a dime.";	[reply] [d/l] [select]
Re: Re: Re: help with algorithm by Zaxo (Archbishop) on Nov 17, 2002 at 01:37 UTC
Sub days() returns a list of names of days, just try: `print "@newtest",$/;` or `for my $day (@newtest) { print $day, $/; }` [download] You are indexing with strings which numify to zero, so you get $newtest["Wednesday"] as $newtest[0]. After Compline, Zaxo	[reply] [d/l] [select]