in reply to Printing Variable Variables

I know this is really dumb and basic but I can't figure it out.
What it is is really unnecessary. This is what arrays are for. Would you care to explain why you don't want to use an array? 
#!/usr/bin/perl -w

use strict;

my @string = qw/Jessy Bob Nancy/;
my $num = 0;
while ( $num < @string ) {
    print "$string[$num] ";
    $num++;
}

### or, instead of a loop, just:

print "\n@string\n";

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update: If the reason for not using an array is that the numeric index can be really large (meaning it can be a very sparse "array"), then this is what hashes are for -- just use the numeric as the hash key instead of as an array index.

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Re^2: Printing Variable Variables
by awohld (Hermit) on Sep 13, 2005 at 07:47 UTC
    I'm trying to make a CGI script that will take two form fields and let a user enter in an unlimited amount of data points. For instance they will select a city and distance, then a second city and distance, then a third... etc..

    You can see by executing my code what I'm trying to do, I just can't get the values from one submission to another to stay.

    Any ideas?
    #!/usr/bin/perl -w

use CGI::Carp qw(fatalsToBrowser);
use strict;
use CGI;

my $cgi = CGI->new();

my $city1 = $cgi->param("city");  # Get a fresh warning point
my $distance1 = $cgi->param("distance");

my @parameterNames = $cgi->param;
my $numCity = 0;  #Counter for all the Cities passed back to the scrip
+t

foreach(@parameterNames){
  if(/city/) { #Check each paramater to see if is a "city" is present
    $numCity++;  #If it is a city, add it to the counter
  }
}


print $cgi->header;

my $action = "help.pl";
print $cgi->start_form(-action=>$action);

my $quit = '1';#Once this # gets high enough, the loop "quits"
 if ($numCity){ #If there are any cities, print them as hidden fields
  while($quit <= $numCity) {

#    my $hiddenCity = "\$city".$quit;
#    my $hiddenCityValue = eval $hiddenCity;

#    my $hiddenDistance = "\$distance".$quit;
#    my $hiddenDistanceValue = eval $hiddenDistance;

    my $hiddenCityName = "city".$quit;
    my $hiddenDistanceName = "distance".$quit;

    my $hiddenCityValue = $cgi->param("$hiddenCityName");
    my $hiddenDistanceValue = $cgi->param("$hiddenDistanceName");

   print $cgi->hidden("$hiddenCityName", "$hiddenCityValue");
   print $cgi->hidden("$hiddenDistanceName", "$hiddenDistanceValue");

   print "$hiddenCityName => $hiddenCityValue<br>";
   print "$hiddenDistanceName=> $hiddenDistanceValue<br><hr>";
   $quit++;
  }
}

print <<EOF;
<select name="city" tabindex="1">
<option value="1">Columbus</option>
<option value="2">Chicago</option>
</select>
&nbsp&nbsp&nbspDistance:&nbsp<input type="text" name="circularWarningD
+istanceStart" size="6" maxlength="6" />
<br>
EOF

print $cgi->submit('Go');
print $cgi->end_form;

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[reply]
[d/l]

      In this particular situation, it looks like you just want to concatenate your cities and distances to those already chosen. You could use a single hidden field for each, something like:

      my @cities,@distances;
if ($cgi->param('hiddenCities')) { # there are cities and distances
                                   # from before
    @cities = split(';',$cgi->param('hiddenCities'));
    @distances = split(';',$cgi->param('hiddenDistances'));
}
if ($cgi->param('Go')) { # form was submitted
    push @cities,$cgi->param('city');
    push @distances,$cgh->param('circularWarningDistanceStart');
}
# put list of cities back on the form
print $cgi->hidden('hiddenCities',join(';',@cities);
print $cgh->hidden('hiddenDistances',join(';',@distances);
# ....
# do more form stuff here
# like asking for more input, etc.

      [download]

      The code above is untested, but I hope that gives you some ideas you could use.

      Sean

[reply]
[d/l]

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