using empty()

[netfrugal]

I just want to make sure I'm not misunderstanding the usage of the empty() function.

Here is one statement:

if($var == ""){ // do something fun here }

Does this essentially mean the same?:

if(empty($var)){ // do something fun here }

[seisei]

i think this one is the right syntax..

if(empty($var)==true){ // do something fun here } 

hehe

[seisei]

While that may be true, those two statements (empty($var), $var == '') are NOT the same. When programming for web interfaces, where a user may be submitting '0' as a valid field value, you should not be using empty().

<?php
$str = '0';

// outputs 'empty'
echo empty($str) ? 'empty' : 'not empty';

// outputs 'not empty'
echo $str == '' ? 'empty' : 'not empty';

?>

got this from php manual hehe

[netfrugal]

That is a good point concerning the '0'. I was thinking of that too. In the situation I am using, I am only looking for empty fields. Such as a text box from a form, where nothing is entered.

[nrg_alpha]

empty()

-NRG

[NogDog]

Actually, each of these will return true with empty(), or when compared to each other with the "==" operator:

$test = array(false, null, 0, '0', '');
foreach($test as $value)
{
   if(empty($value))
   {
      echo "Empty<br />\n";
   }
   else
   {
      echo "Full<br />\n";
   }
}

Outputs:

Empty
Empty
Empty
Empty
Empty

If you want to verify that something was entered, even if it's a 0, then you need to use the 'identical' or 'not identical' comparison operators ("===" or "!=="):

$test = array(false, null, 0, '0', '');
foreach($test as $value)
{
   if(trim($value) === '')
   {
      echo "Empty<br />\n";
   }
   else
   {
      echo "Full<br />\n";
   }
}

Outputs:

Empty
Empty
Full
Full
Empty