empty

Example 1377. Test whether a single value is empty

$value = '';

if (empty ($value))
    print "Variable <i>\$value</i> is empty.\n\n";
else
    print "Variable <i>\$value</i> is not empty.\n\n";


// Alternate syntax for the same test
// Because of the if statement, $value is evaluated in a true/false context
// .. basically meaning that non-empty and non-zero means true.
if ($value)
    print "Variable <i>\$value</i> is empty.\n\n";
else
    print "Variable <i>\$value</i> is not empty.\n\n";


// Another alternate syntax for the same test using the == operator
if ($value == 0)
    print "Variable <i>\$value</i> is empty.\n\n";
else
    print "Variable <i>\$value</i> is not empty.\n\n";


// Test whether a $value actually contains an empty string or 0 using the === operator
if ($value === '')
    print "Variable <i>\$value</i> contains an empty string.\n\n";
else if ($value === array ())
    print "Variable <i>\$value</i> contains an empty array.\n\n";
else if ($value === 0)
    print "Variable <i>\$value</i> contains 0.\n\n";
else if ($value === NULL)
    print "Variable <i>\$value</i> contains NULL.\n\n";
else
    print "Variable <i>\$value</i> does not contain an empty string or a 0.\n\n";

Example 1378. Make sure that a value contains something other than an empty string or 0

<pre>
<?
// Make a list of values to test
$values = array(
    'An empty string ("")' => "", 0 => 0, 1 => 1, 'foo' => 'foo',
    'A single space (" ")' => " ", "'000'" => '000', '000' => 000
);

// Loop through the values
// Show what they look like before and after conversion
foreach ($values as $key => $value) {
    $is_empty = empty ($value) ? 'empty' : 'not empty';
    printf ("<b>%-24s</b> %s\n", $key, "Value is $is_empty");
}
?>
</pre>