[RESOLVED] Printing passed variable names in a function

Aybabtu

I am trying to write a function to check for invalid entries in a form. What I want to do is echo an error message with the variable name that is in error. Like so:

function nodata($fieldname)
 { 
  if(strlen($fieldname) <= 1)
   {

   echo 'You must enter a value for $fieldname<BR>';
   return true;
   }
  }

When I run this I just get: You must enter a value for $fieldname.

Is there a way I can can get: "You must enter a value for $username" if I passed the variable $username into the function?

laserlight

I suggest that you pass the variable name to the function.

etully

I think what you want is:

function nodata($fieldname) {
global $$fieldname;
if(strlen($$fieldname) <= 1) {
echo "You must enter a value for $fieldname<BR>";
return true;
}
}

Note the double dollar sign in the strlen function.
Note the double quotes in the echo statement.
Note that the variable has to be made global so that it's accessible to the function.

Personally, you are using an approach that I wouldn't tend to use but technically it works, so I guess it's a matter of opinion.

Aybabtu

The logic portion of my code was working with no problems. What I need is when I pass $random_variable_name into the function I want it to echo ""You must enter a value for $random_variable_name" instead of $fieldname.

I tried your code but I get: "You must enter a value for"

Does this explain more?

etully

Part of the reason that this is complicated is that there are lots of ways to accomplish this function and I am taking your lead and doing it your way - which is a way that I wouldn't necessarily do it myself. But let's assume that we do it your way for a minute.

Let's say you have a field called $customername and it's currently equal to "John Smith".

One way to solve the problem is to pass "John Smith" to the function. Of course, as you pointed out, this won't allow the function to know which variable was being evaluated.

So the other way to solve the problem is to pass "customername" to the function. I don't mean pass $customername. I mean, pass the string "customername". c - u - s - t - o - m - e - r - n - a - m - e.

Now, once the function has that string, it can make a variable variable. So if your function receives $fieldname, then the variable $fieldname is equal to "customername". And once the function knows that, then it can check the contents of $$fieldname. When you replace ($fieldname) with "customername", then you end up with $customername.

And that would be fine. Then you could say:

if (strlen($$fieldname)>1) { blah blah blah

EXCEPT that $customername DOESN'T HAVE ANY VALUE inside the function. Why? Because that variable isn't local to the function. So you have to use the global command to make $$fieldname (which is $customername) local to the function.

In other words, my code works fine as long as you pass the NAME of the variable that should be evaluated. Don't pass the variable to be evaluated - pass the NAME of the variable to be evaiuated. (Just as laserlight suggested).

Aybabtu

Thank you for the reply, but I think I figurend out an easier way to do it. I was trying to complicate things more that it should be. I wrote the following and it does what I want.

function nodata($fieldname, $fieldname2)
 { 
  if(strlen($fieldname) <= 0)
   {

   echo '<B>'.func_get_arg(1).'</B> can not be blank.  Please go back and enter a value.<BR>';
   //echo func_get_arg(1);
   $error=1;
   return $error;
   }
  }

now I can do the following:

nodata($_GET['position'], 'Position');

and I get "Position can not be blank. Please go back and enter a value."

Now I do have a second question. How do I return $error back to my script so the following logic will work?

if ($error == 1)
  { die; }

etully

Excellent. As I said, you were not doing it the way I would suggest. I like your second technique much better.

So to answer your return error question, you need to do two things:

First, you are returning a "1" if there is an error but you are not returning anything if there is no error. Therefore, add an "else" statement that says "return 0;"

Second, outside of the function, $error isn't going to have a value but that's ok because you don't want to evaluate $error... you want to evaluate the function like this:

if (nodata($_GET['position'], 'Position')==1)
{ die; }

Aybabtu

Thanks for all of the help, I also figured this one out before I cam back as well. Maybe I should think a little more before I post. Here is how I am doing it now.

function nodata($fieldname, $fieldname2)
 { 
  if(strlen($fieldname) <= 0)
   {

   echo '<B>'.func_get_arg(1).'</B> can not be blank.<BR>';
   return 1;
   }
  }

and then I just do the following:

$error = nodata($_GET['return_by'], 'Apply by');

 if ($error == 1)
  { die; }

Thanks again for all of the help and suggestions.

Aybabtu.