is_nullExampleExample 1393. Test whether a single value is NULL // Define a variable to use in testing $test = TRUE; is_null ($test) or die ('Variable $test is not NULL'); Example 1394. Test whether a few different values are NULL <pre> <?php // Make a list of values to test $values = array ( 'empty string ("")' => '', 'Zero (0)' => 0, 'TRUE' => TRUE, "'Hello'" => 'Hello', 'empty array' => array(), 'NULL' => NULL ); // Loop through the values and test whether they are objects foreach ($values as $key => $value) { $is_null = is_null ($value) ? 'Yes' : 'No'; printf ("<b>%'.-45s</b>%'.3s\n", $key, $is_null); } ?> </pre>
PHP Functions Essential Reference. Copyright © 2002 by New Riders Publishing
(Authors: Zak Greant, Graeme Merrall, Torben Wilson, Brett Michlitsch).
This material may be distributed only subject to the terms and conditions set forth
in the Open Publication License, v1.0 or later (the latest version is presently available at
http://www.opencontent.org/openpub/).
The authors of this book have elected not to choose any options under the OPL. This online book was obtained
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and is designed to provide information about the PHP programming language, focusing on PHP version 4.0.4
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