Variable Selection

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

Hey Monks
I have an array with values, a hash with info on those values and a variable.
What I need is a piece of code that will cycle through the array to see if something matches the variable. If it does its info gets added to the @result_array and if not the variable itself gets added to the @result_array.
So if the variable was var1 as below the @result_array would contain "info1" however if the variable was something like var67 the @result_array would contain "var67".

my %hash ={"var1", "info1", "var2", "info2", "var3", "info3"};
my @array=("var1","var2","var3");
my $where = "var1";
my $used = 0;

foreach my $item(@array){
   if ($item eq $where)
   {
      push @result_array, $hash{$item};
      $used = 1;
   }
}
unless ($used = 1){
push @result_array, $where;
}
$used = 0;
[download]

Thanks everybody

j o h n i r l .

Sum day soon I'Il lern how 2 spelI (nad tYpe)

Comment on Variable Selection Select or Download Code

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Re: Variable Selection by tommyw (Hermit) on Aug 30, 2002 at 10:06 UTC
The absolute simplest fix to your code would be to initialise the hash correctly; round brackets not curly: `my %hash =("var1", "info1", "var2", "info2", "var3", "info3");` [download] , and you've broken the equality test in your unless clause: ==, not =. The perlish rewrite of your code would be: `if (grep {$_ eq $where} @array) { push @result_array, $hash{$where}; } else { push @result_array, $where; }` [download] Update: Of course, if the array is simply the keys of the hash, it gets even easier: `push @result_array, $hash{$where} \|\| $where;` [download] -- Tommy Too stupid to live. Too stubborn to die.	[reply] [d/l] [select]
Re: Variable Selection by fruiture (Curate) on Aug 30, 2002 at 10:04 UTC
Check perldata why your hash initialization is broken. check perlsyn for last. Check perlop for the meaning of '=' and '==' and then think of totally leaving the @array out of your code and directly looking for $where in the %hash, via exists. HTH -- http://fruiture.de	[reply]
Re: Variable Selection by Preceptor (Deacon) on Aug 30, 2002 at 10:04 UTC
how about: `foreach my $item ( @array ) { if ( $item eq $where ) { push ( @result_array, ( $hash{$item} ) ? $hash{$item} : $item ); } }` [download]	[reply] [d/l]