note 59782 deleted from function.is-null by bjori
| From: | bjori@php.net | Date: | Wed, 03 May 2006 13:04:49 +0000 |
| Subject: | note 59782 deleted from function.is-null by bjori | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-110450@lists.php.net to get a copy of this message | ||
Note Submitter: jsjacobs at piercedmedia dot com
----
I have variables that may be set to empty ($test = "";) when passed into a fuction and as
such may be set, but not null, but still empty. I wanted to know the difference between these so I
created a test displaying all errors. (I hate even seeing notices).
first I check isset, is_null, and empty on an unset variable, then set the variable empty ($test =
"";)
<?php
error_reporting(2047);
if(is_null($test))
{
print 'This is Null<BR>';
}
else
{
print 'Not Null<BR>';
}
if(isset($test))
{
print 'This is Set<BR>';
}
else
{
print 'This is Not Set<BR>';
}
if(empty($test))
{
print 'This is Empty<BR>';
}
else
{
print 'This is Not Empty<BR>';
}
$test = '';
if(is_null($test))
{
print 'This is Null<BR>';
}
else
{
print 'This is Not Null<BR>';
}
if(isset($test))
{
print 'This is Set<BR>';
}
else
{
print 'This is Not Set<BR>';
}
if(empty($test))
{
print 'This is Empty<BR>';
}
else
{
print 'This is Not Empty<BR>';
}
?>
And the results
----------------------------------------------
Notice: Undefined variable: test in /var/www/htdocs/test.php on line 4
This is Null
This is Not Set
This is Empty
This is Not Null
This is Set
This is Empty
We can conclude that is_null will error on an unset variable, and thus is not the same as isset.