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

Hi Monks!
I am trying to build a dropdown menu with dynamic values, but I cant make this thing work, can any one show me if here is a better way to get this done? I do need to store the value in one variable to use it later, that's where my issue is, thanks for the help! 
#!/usr/bin/perl

use CGI::Carp qw(fatalsToBrowser set_message);
use CGI qw(-oldstyle_urls :standard);       

print header();

my @acc = qw(12345 67895 123445 112288 3736666 445899);

my $c=0;

my $dmenu="<select name=dropdown>".
      
foreach my $accs(@acc)
  {
    $c++;      
    "<OPTION value=$c>$accs</OPTION>".
          
  }

"</select>";
            
            
            
print $dmenu;

[download]

Replies are listed 'Best First'.
Re: Dynamic menu options
by Your Mother (Archbishop) on Jul 28, 2010 at 19:06 UTC

    I think this is a *much* better approach- 

    use warnings;
use strict;
use CGI qw(:standard);

my @acc = qw( 12345 67895 123445 112288 3736666 445899 );

print popup_menu({
    -name => "account",
    -values => \@acc,
});

    [download]

    .= in HTML/string generation is a danger sign (in my book; it's on sale, 2¢ this week).

[reply]
[d/l]
[select]
      What do you mean danger sign? Besides, that was a typo on OPs part, using . instead of ;
[reply]

        ".=" wasn't a typo. Concatting strings like that has, to me at least, a huge code smell. It's a sign that you are doing things in a suboptimal, if not terrible, way.

[reply]
Re: Dynamic menu options
by kennethk (Abbot) on Jul 28, 2010 at 17:51 UTC
    I suspect the issue is that you are not storing your strings in $dmenu as you go through. You seem to be using a foreach loop in place of map - Perl tells you this is a syntax error. Perhaps you mean: 

    #!/usr/bin/perl

use CGI::Carp qw(fatalsToBrowser set_message);
use CGI qw(-oldstyle_urls :standard);       

print header();

my @acc = qw(12345 67895 123445 112288 3736666 445899);

my $c=0;

my $dmenu="<select name=dropdown>";
      
foreach my $accs(@acc)
  {
    $c++;      
    $dmenu .= "<OPTION value=$c>$accs</OPTION>";
          
  }

$dmenu .= "</select>";
            
            
            
print $dmenu;

    [download]

    Note I have used the concatenating assignment operator .= (see Assignment Operators, Additive Operators).

    Update: Copy paste fail fixed.

[reply]
[d/l]
[select]
      Yes it makes sense, but it is needed to remove the "my" from $dmenu inside "foreach" and last line of the code.
      How could I delimit the values on the array to display only 4 numbers instead of all of them? Cause sometimes I will have years stored in there and I don't need to display more them 4 years starting from current year backwards, could I use "pull"?
[reply]
        If "pull" corresponds to shift, then yes. You can swap your loop variable to $c (though the only single-letter variables that are generally considered good form are $i, $j, $x, $y and $z) and use a shift to get the array member, which would destroy the array in the process. You could also use indices on the array to the same end. 

        #!/usr/bin/perl

use CGI::Carp qw(fatalsToBrowser set_message);
use CGI qw(-oldstyle_urls :standard);       

print header();

my @acc = qw(12345 67895 123445 112288 3736666 445899);

my $dmenu="<select name=dropdown>";
      
my $count = 4;
foreach my $c (1 .. $count)
  {
    my $accs = shift @acc;
    $dmenu .= "<OPTION value=$c>$accs</OPTION>";
          
  }

$dmenu .= "</select>";
            
            
            
print $dmenu;

        [download]
[reply]
[d/l]
[select]

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