empty() and isset()

[sissy]

Hi folks,

Just wondering what the synopsis is on using the empty() and isset() tags.

Do you just stick with one or use both depending on the situation.

From what i have read they use it like so

isset($var) or !isset($var)

and

empty($POST['var']) or !empty($POST['var'])

Is this the way it should be used?? just wondering if there are some rules to follow.

Some input here would be great, thanks.

[Weedpacket]

They have different behaviours; you use whichever one is appropriate
given the circumstances.

<?php
error_reporting(E_ALL);

$zero = 0;
$one = 1;
$null = null;
?>
<table border="1">
<tr><th>$var</th><th>$var is not false</th><th>$var is set</th><th>$var is empty</th></tr>
<tr><td>$zero=0</td>
<td><?php echo ($zero) ? '$zero is not false' : '$zero is false';?></td>
<td><?php echo (isset($zero)) ? '$zero is set' : '$zero is not set';?></td>
<td><?php echo (!empty($zero)) ? '$zero is not empty' : '$zero is empty';?></td>
</tr>
<tr><td>$one=1</td>
<td><?php echo ($one) ? '$one is not false' : '$one is false';?></td>
<td><?php echo (isset($one)) ? '$one is set' : '$one is not set';?></td>
<td><?php echo (!empty($one)) ? '$one is not empty' : '$one is empty';?></td>
<tr><td>$null=null</td>
<td><?php echo ($null) ? '$null is not false' : '$null is false';?></td>
<td><?php echo (isset($null)) ? '$null is set' : '$null is not set';?></td>
<td><?php echo (!empty($null)) ? '$null is not empty' : '$null is empty';?></td>
</tr>
<tr><td></td>
<td><?php echo ($undef) ? '$undef is not false' : '$undef is false';?></td>
<td><?php echo (isset($undef)) ? '$undef is set' : '$undef is not set';?></td>
<td><?php echo (!empty($undef)) ? '$undef is not empty' : '$undef is empty';?></td>
</tr>
</table>