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");
?>
Output
True True True True True True True True
PHP empty() Function – FAQs
Does empty() return true for 0?
Yes, empty() returns true for the integer 0 as it is considered an empty value.
Does empty() generate a warning for undefined variables?
No, empty() does not generate a warning or notice for undefined variables. It simply returns true if the variable is not set.
How is empty() different from isset()?
empty() checks if a variable has no value (e.g., 0, null, false), while isset() checks if a variable is set and not NULL.
Does empty() treat false as empty?
Yes, empty() treats false as an empty value and returns true for it.
Can empty() be used to check for non-empty values?
Yes, you can use !empty() to check if a variable contains a non-empty value, such as 1, “text”, or a non-empty array.
