PHP empty() Function

The empty() function in PHP checks whether a variable is empty. It returns true if the variable has a value considered "empty," such as 0, null, false, an empty string, or an unset variable, and false otherwise.

Syntax

bool empty ( $var )

Parameter:

This function accepts a single parameter as shown in above syntax and described below.

• $var: Variable to check whether it is empty or not.

Note: Below version of PHP 5.5, empty() only supports variables, anything other will result in a parse error. The following statement will not work empty(trim($var)). Instead, use trim($name) == false.

Return Value: It returns FALSE when $var exists and has a non-empty, non-zero value. Otherwise it returns TRUE. These values are considered to be as an empty value:

• "" (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)

Example: In this example we demonstrates the empty() function, which returns true for variables that are empty, such as 0, "0", NULL, false, empty arrays, empty strings, and undefined variables.

<?php
    
    // PHP code to demonstrate working of empty() function
    $var1 = 0;
    $var2 = 0.0;
    $var3 = "0";
    $var4 = NULL;
    $var5 = false;
    $var6 = array();
    $var7 = "";
    
    // for value 0 as integer
    empty($var1) ? print_r("True\n") : print_r("False\n");
    
    // for value 0.0 as float
    empty($var2) ? print_r("True\n") : print_r("False\n");
    
    // for value 0 as string
    empty($var3) ? print_r("True\n") : print_r("False\n");
    
    // for value Null
    empty($var4) ? print_r("True\n") : print_r("False\n");
    
    // for value false
    empty($var5) ? print_r("True\n") : print_r("False\n");
    
    // for array
    empty($var6) ? print_r("True\n") : print_r("False\n");
    
    // for empty string
    empty($var7) ? print_r("True\n") : print_r("False\n");
    
    // for not declare $var8
    empty($var8) ? print_r("True\n") : print_r("False\n");

?>

True
True
True
True
True
True
True
True