PHP 7.2.0 Release Candidate 4 Released

Variable handling Functions

Table of Contents

  • boolval — Get the boolean value of a variable
  • debug_zval_dump — Dumps a string representation of an internal zend value to output
  • doubleval — Alias of floatval
  • empty — Determine whether a variable is empty
  • floatval — Get float value of a variable
  • get_defined_vars — Returns an array of all defined variables
  • get_resource_type — Returns the resource type
  • gettype — Get the type of a variable
  • import_request_variables — Import GET/POST/Cookie variables into the global scope
  • intval — Get the integer value of a variable
  • is_array — Finds whether a variable is an array
  • is_bool — Finds out whether a variable is a boolean
  • is_callable — Verify that the contents of a variable can be called as a function
  • is_double — Alias of is_float
  • is_float — Finds whether the type of a variable is float
  • is_int — Find whether the type of a variable is integer
  • is_integer — Alias of is_int
  • is_iterable — Verify that the contents of a variable is an iterable value
  • is_long — Alias of is_int
  • is_null — Finds whether a variable is NULL
  • is_numeric — Finds whether a variable is a number or a numeric string
  • is_object — Finds whether a variable is an object
  • is_real — Alias of is_float
  • is_resource — Finds whether a variable is a resource
  • is_scalar — Finds whether a variable is a scalar
  • is_string — Find whether the type of a variable is string
  • isset — Determine if a variable is set and is not NULL
  • print_r — Prints human-readable information about a variable
  • serialize — Generates a storable representation of a value
  • settype — Set the type of a variable
  • strval — Get string value of a variable
  • unserialize — Creates a PHP value from a stored representation
  • unset — Unset a given variable
  • var_dump — Dumps information about a variable
  • var_export — Outputs or returns a parsable string representation of a variable
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User Contributed Notes 4 notes

skelley at diff dot nl
16 years ago
Sorry to say Mykolas, but your definition would not be correct.

isempty() evaluates to true for NULL, 0, "", false or 'not set' for any variable, object etc. that can be set to a value.

isset() evaluates to true if the variable, object etc. exists at all, whether it is 'empty' or not.

$foo = 0;
isset($foo); //will evaluate to true.
!empty($foo); //will evaluate to false.

isset($foo); //will evaluate to false.
!empty($foo); //will evaluate to false.
jfrasca at sheerdev dot com
12 years ago
I needed a simple function that would reduce any kind of variable to a string or number while retaining some semblance of the data that was stored in the variable. This is what I came up with:

function ReduceVar ($Value) {
    switch (gettype($Value)) {
        case "boolean":
        case "integer":
        case "double":
        case "string":
        case "NULL":
            return $Value;
        case "resource":
            return get_resource_type($Value);
        case "object":
            return ReduceVar(get_object_vars($Value));
        case "array":
            if (count($Value) <= 0)
                return NULL;
                return ReduceVar(reset($Value));
            return NULL;
2 years ago
If you want to find out the datatype of a variable, use PHP's native gettype() function instead of various custom implementations.
coding-kid at hotmail dot com
7 years ago
A simple method to check what type input var is:

class filter{
     * @var: $types (array): holds all the supported datatypes, their number, and the callback that need to be made
     *                             to check if it's valid.
    private $types = array('string'=> array('number'=> '1', 'callback'=> 'is_string'),
                            'int'=> array('number' => '2', 'callback' => 'is_int'),
                            'array'=> array('number' => '3', 'callback' => 'is_array'),
                            'object'=> array('number' => '4', 'callback' => 'is_object'),
                            'float'=> array('number' => '5', 'callback' => 'is_float'),
                            'bool'=> array('number' => '6', 'callback' => 'is_bool'),
                            'resource'=> array('number' => '7', 'callback' => 'is_resource'),
                            'null'=> array('number' => '8', 'callback' => 'is_null'));

    function __construct(){
     * @desc: This method checks what type the input variable is
     * @param: $var (mixed): The var that will be checked
     * @param: $output_type (string): How the result will be returned
     * @returns: string or int
    function type($var, $output_type = 'numeric'){

            $var_type = array("string", "1");
        } elseif(is_int($var)){
            $var_type = array("int", "2");
        } elseif(is_array($var)){
            $var_type = array("array", "3");
        } elseif(is_object($var)){
            $var_type = array("object", "4");
        } elseif(is_float($var)){
            $var_type = array("float", "5");
        } elseif(is_bool($var)){
            $var_type = array("bool", "6");
        } elseif(is_resource($var)){
            $var_type = array("resource", "7");
        } elseif(is_null($var)){
            $var_type = array("null", "8");
        if($output_type == 'text'){
            return $var_type[0];
        } else{
            return $var_type[1];
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