PHP Functions Essential Reference

empty

bool empty(mixed variable) 

Tests whether a variable is defined and contains a non-empty and nonzero value.

Returns:

TRUE if the variable is empty or undefined; FALSE otherwise

Description:

empty() checks whether the argument passed is a defined variable that contains a value other than an empty array, empty string, 0 (zero), or NULL. empty() should be used only on variables—if the function is used on a value, it generates a parse error.

Availability:

UNIX, Windows

Version:

3+, 4+

See also:

To compare one value to another:

==, ===, !=, !==, <, >, <=, >= operators

To test whether a variable is set:

isset() 

Examples:

Test whether a single value is empty

$value = ''; if (empty ($value)) print "Variable <i>\$value</i> is empty.\n\n"; else ...