Considering that the main impetus for these threads is to write code that does not generate the notice regarding missing variables or indices, neither isset() or empty() will provide that completely.
If a variable is declared, but assigned null, it is not set and it is empty. But so what. The variable exists and will not generate a notice if access is attempted. No suppression of the non existent notice is necessary. The issue is one of undefined variables and indices. That's what the E_NOTICE says ... Notice: Undefined variable Notice: Undefined index To directly detect the presence of a key, then array_key_exists() is the function that covers the requirement. Global variables are easily detectable using array_key_exists($key, $GLOBALS); Properties for an object ... property_exists(). For locally scoped variables, the function get_defined_vars() can be combined with array_key_exists(). But the obvious overhead of having to extract all the variables into a temp array is probably going to be a performance no-no. The script below (and in [1] in case the formatting all goes wonky), demonstrates this. Ideally, a construct that specifically detects if a variable is declared, irrespective of its value, would be the perfect solution as this could be combined with isset() or empty() as the developer needs. Richard. [1] http://pastebin.com/qLNYtfAw <?php error_reporting(-1); function report($desc, $isset, $empty, $defined) { return $desc . ' isset() = ' . ($isset ? 'true ' : 'false') . ' empty() = ' . ($empty ? 'true ' : 'false') . ' defined = ' . ($defined ? 'true ' : 'false') . PHP_EOL; } function tester() { // $undefined_variable = ''; $defined_variable_null_value = null; $defined_variable_value = 'non null variable'; $array = array( // 'undefined_key' => '', 'defined_key_null_value' => null, 'defined_key_value' => 'non null element', ); $defined_vars = get_defined_vars(); echo report('Undefined variable ', isset($undefined_variable), empty($undefined_variable), array_key_exists('undefined_variable', $defined_vars)), report('Defined variable null value ', isset($defined_variable_null_value), empty($defined_variable_null_value), array_key_exists('defined_variable_null_value', $defined_vars)), report('Defined variable non-null value ', isset($defined_variable_value), empty($defined_variable_value), array_key_exists('defined_variable_value', $defined_vars)), report('Undefined key ', isset($array['undefined_key']), empty($array['undefined_key']), array_key_exists('undefined_key', $array)), report('Undefined key null value ', isset($array['defined_key_null_value']), empty($array['defined_key_null_value']), array_key_exists('defined_key_null_value', $array)), report('Undefined key non-null value ', isset($array['defined_key_value']), empty($array['defined_key_value']), array_key_exists('defined_key_value', $array)); } tester(); ?> -- Richard Quadling Twitter : EE : Zend @RQuadling : e-e.com/M_248814.html : bit.ly/9O8vFY -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
