How to use empty values in an array?

Question

I have been trying to shorten this code:

if(empty($soort))
{
    $error = 'ja';
    $error_soort = 'ja';
    $error_omschr_soort = $lang['error_no_entry'];
}

if(empty($klant_id))
{
    $error = 'ja';
    $error_klant_id = 'ja';
    $error_omschr_klant_id = $lang['error_no_entry'];
}

if(empty($contact_id))
{
    $error = 'ja';
    $error_contact_id = 'ja';
    $error_omschr_contact_id = $lang['error_no_entry'];
}

if(empty($aflever_id))
{
    $error = 'ja';
    $error_aflever_id = 'ja';
    $error_omschr_aflever_id = $lang['error_no_entry'];
}

if(empty($klant_ref))
{
    $error = 'ja';
    $error_klant_ref = 'ja';
    $error_omschr_klant_ref = $lang['error_no_entry'];
}

if(empty($materiaal))
{
    $error = 'ja';
    $error_materiaal = 'ja';
    $error_omschr_materiaal = $lang['error_no_entry'];
}

if(empty($dikte))
{
    $error = 'ja';
    $error_dikte = 'ja';
    $error_omschr_dikte = $lang['error_no_entry'];
}

To this much shorted code:

$check_empty = array($soort, $klant_id, $contact_id, $aflever_id, $klant_ref, $materiaal, $dikte);

foreach ($check_empty as $check)
{
    if(empty($check))
    {
        $error = 'ja';
        $error_check = 'ja';
        $error_omschr_check = $lang['error_no_entry'];
    }
}

The new code is not working. It seems (of course(?)) because if any of the values I want to check if they are empty they are not put in the array since an array can not hold empty values?

How can I make the original code shorter?

Of course an array can hold empty values. See: $foo = array('');. It is an array containing an empty string. What is that is not working? What should happen? What happens? — Felix Kling
– Felix Kling, Commented Jun 26, 2011 at 11:49

Gumbo · Accepted Answer · 2011-06-26 11:57:50Z

You are missing the keys/variable names. Instead of storing the variable values in the array, you could just store the keys/variable name and thus be able to identify the key/variable that is empty:

$check_empty = array('soort', 'klant_id', 'contact_id', 'aflever_id', 'klant_ref', 'materiaal', 'dikte');
$errors = array();
foreach ($check_empty as $name) {
    if (empty($$name)) {
        $errors[] = array(
            'name' => $name,
            'desc' => $lang['error_no_entry']
        );
    }
}

Here $$name is a variable variable where the value of $name is used to identify the variable. And as the errors are stored in an array, you can check whether there are errors by check whether $errors is empty:

if (empty($errors)) {
    // no errors
} else {
    // errors
}

Then you can even iterate the errors with foreach.

Karoly Horvath · Accepted Answer · 2011-06-26 11:49:49Z

0

The short answer is: http://php.net/manual/en/language.variables.variable.php

If this doesn't help I'll update the answer ;)

answered Jun 26, 2011 at 11:49

Karoly Horvath

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Comments

Pekka · Accepted Answer · 2011-06-26 11:50:30Z

In your specific case, you would have to work with variable variables:

    ${"error_".$check} = 'ja';
    ${"error_omschr_".$check} = $lang['error_no_entry'];

however, variable variables are regarded very bad practice. The variables built this way are impossible to document using phpDoc, for example. Also, your IDE's auto-lookup mechanism will fail for them.

It is much better to use an array:

    // Earlier in the code
    $error = array();
    $error_omschr = array();

   // In your loop
    $error[$check] = "ja";  // you may want to use booleans instead
    $error_omschr[$check] = $lang['error_no_entry'];

    // later, for example....
    foreach ($error as $key => $value)
     {
       if ($value == 'ja') 
         echo "Error: $key<br>";
     }

Also, as pointed out by Gumbo and Felix Kling, you need to fix your array definition.

I assume that $check is the value so that would not work. Better to use compact here to create the array and then loop over name and value.
@Felix $check would be each field name as shown in the OP's code (obviously after fixing the array definition, though, as shown by Gumbo).

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