empty Determine whether a variable is empty &reftitle.description; boolempty mixedvar Determine whether a variable is considered to be empty. A variable is considered empty if it does not exist or if its value equals &false;. empty does not generate a warning if the variable does not exist. &reftitle.parameters; var Variable to be checked Prior to PHP 5.5, empty only supports variables; anything else will result in a parse error. In other words, the following will not work: empty(trim($name)). Instead, use trim($name) == false. No warning is generated if the variable does not exist. That means empty is essentially the concise equivalent to !isset($var) || $var == false. &reftitle.returnvalues; Returns &false; if var exists and has a non-empty, non-zero value. Otherwise returns &true;. The following things are considered to be empty: "" (an empty string) 0 (0 as an integer) 0.0 (0 as a float) "0" (0 as a string) &null; &false; array() (an empty array) $var; (a variable declared, but without a value) &reftitle.changelog; &Version; &Description; 5.5.0 empty now supports expressions, rather than only variables. 5.4.0 Checking non-numeric offsets of strings returns &true;. &reftitle.examples; ]]> PHP 5.4 changes how empty behaves when passed string offsets. ]]> &example.outputs.53; &example.outputs.54; &reftitle.notes; ¬e.language-construct; When using empty on inaccessible object properties, the __isset() overloading method will be called, if declared. &reftitle.seealso; isset __isset() unset array_key_exists count strlen The type comparison tables