eval() on indexed value

Posted on 2002-06-10
Medium Priority
Last Modified: 2011-10-03
I have a form that submits multiple hidden fields. Part of this form submits a field called  $orderline1 (40 total -  $orderline1 - $orderline401). I'm trying to determine how many fields have data but I keep getting errors with my eval!

I have tried:

$cnt = 1;
$orders = 1;
     while ($orders){
          eval("if($OrderLine"+$cnt+" != '')"){
          echo $cnt;
          }else{ $orders = 0;}


I have also tried the eval line as:

if(eval("$OrderLine"+$cnt) != ""){

But I can't get the eval to work! Is this the best way to figure out how many fields have data and if so what is the eval statement. If not then what is the best way?
Question by:sargento
  • 5
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LVL 32

Expert Comment

ID: 7068100
Why use eval?

Couldn't use variablevariable ?

Instead of eval("if($OrderLine"+$cnt+" != '')"){


$tmpVar = $OrderLine.$cnt;

And also: You don't use + in PHP. Use "."

Author Comment

ID: 7068181
$tmpVar = $OrderLine.$cnt; produces a number which is only the count (value of $cnt). I need to know somehow if
$Orderline1 holds any data and if $Orderline2 holds any data etc.

I'm just trying to index thru $Orderline# (somehow) and find out how many fields hold data.
LVL 32

Expert Comment

ID: 7068183
That's why I'm using double $$ (also called variablevariable)

This is wrong


This is RIGHT:

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LVL 32

Accepted Solution

Batalf earned 200 total points
ID: 7068187
Or maybe this is right

$tmpVar = "OrderLine".$cnt;


If you do this

$tmpVar will be "OrderLine1" if $cnt is 1. Then if($$tmpVar.. is the same as if($OrderLine1)

Author Comment

ID: 7068188
Just to clarify a little further this is psrt of the form structure:

<input type="HIDDEN" name="OrderLine1"        value="">
                                                                      <input type="HIDDEN" name="OrderLine2"        value="">
                                                                      <input type="HIDDEN" name="OrderLine3"        value="">

which goes upto 40!
LVL 32

Expert Comment

ID: 7068191
If this is the case, my last comment will solve your problem

$tmpVar = "OrderLine".$cnt; // $tmpVar = "OrderLine1" if $cnt is 1
if($$tmpVar!=""){ // The same as if($OrderLine1!=""){
LVL 32

Expert Comment

ID: 7068200
Thank you!

An other solution is to use an array in your form. Instead of OrderLine1 you could use OrderLine[1]. Then you have an array called $OrderLine when you submit the form. You could easily loop through this form.

THe form:

<input type="HIDDEN" name="OrderLine[1]"        value="">
                                                                     <input type="HIDDEN" name="OrderLine[2]"
                                                                     <input type="HIDDEN" name="OrderLine[3]"

PHP code after submission:

  // Other Code

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