Criticize this form validation, please

[dshevnock]

I have a signup form that has 19 small textboxes that will be populated with one number PER textbox from the user. The textboxes on the signup form are respectively called: card1, card2, card3....card18, card19. For my form validation, I know I could do the longhand version of:

 

[pre]

if(isset($_POST['card1'] && $_POST['card1'] != "" && is_numeric($_POST['card1']) && strlen($_POST['card1']) == 1) {

    //proceed

}

else{

    // setup error message(s)

}

[/pre]

 

...and reproduce this for the other 18 textboxes relatively easily, but I would rather learn the more efficient and correct way to do. Here is what I came up with:

 

[pre]

for ($i = 1; $i<=19;$i++){

$var = 'card'.$i;

$temp = $_POST[$var];

if($$var == "" || !is_numeric($$var) || strlen($$var) != 1){

// error message of some sort

}

}

[/pre]

 

Any criticism/suggestions? I don't cry for that long and I don't hold grudges, so please come with it 

 

[per1os]

Why are you using the $$... that is used to create a variable out of the data of $var...

 

<?php
for ($i = 1; $i<=19;$i++){
   $var = 'card'.$i;
   if(!isset($_POST[$var]) || $_POST[$var] != "" || !is_numeric($_POST[$var]) || strlen($_POST[$var]) != 1){
      // error message of some sort
   }
}
?>

 

Would be better, as incase notices are on the assigning of the $temp variable would throw a notice error if the variable was not an index.

[dshevnock]

Why are you using the $$... that is used to create a variable out of the data of $var...

 

This is the first time I have researched and used the $$ syntax before. I guess I miss understood it's exact use.

 

 

[pre]<?php

for ($i = 1; $i<=19;$i++){

  $var = 'card'.$i;

  if(!isset($_POST[$var]) || $_POST[$var] != "" || !is_numeric($_POST[$var]) || strlen($_POST[$var]) != 1){

      // error message of some sort

  }

}

?>[/pre]

 

Would be better, as incase notices are on the assigning of the $temp variable would throw a notice error if the variable was not an index.

 

Thanks for the advice! i didn't even think using a combination of the two possibilities.