Uneven division of an integer variable by another integer variable will result in a float by automatic conversion -- you do not have to cast the variables to floats in order to avoid integer truncation (as you would in C, for example):$dividend = 2;$divisor = 3;$quotient = $dividend/$divisor;print $quotient; // 0.66666666666667

Cast operators have a very high precedence, for example (int)$a/$b is evaluated as ((int)$a)/$b, not as (int)($a/$b) [which would be like intdiv($a,$b) if both $a and $b are integers].The only exceptions (as of PHP 8.0) are the exponentiation operator ** [i.e. (int)$a**$b is evaluated as (int)($a**$b) rather than ((int)$a)**$b] and the special access/invocation operators ->, ::, [] and () [i.e. in each of (int)$a->$b, (int)$a::$b, (int)$a[$b] and (int)$a($b), the cast is performed last on the result of the variable expression].

Casting objects to arrays is a pain. Example:<?phpclass MyClass {    private $priv = 'priv_value';    protected $prot = 'prot_value';    public $pub = 'pub_value';    public $MyClasspriv = 'second_pub_value';}$test = new MyClass();echo '<pre>';print_r((array) $test);/*Array(    [MyClasspriv] => priv_value    [*prot] => prot_value    [pub] => pub_value    [MyClasspriv] => second_pub_value) */?>Yes, that looks like an array with two keys with the same name and it looks like the protected field was prepended with an asterisk. But that's not true:<?phpforeach ((array) $test as $key => $value) {    $len = strlen($key);    echo "{$key} ({$len}) => {$value}<br />";    for ($i = 0; $i < $len; ++$i) {        echo ord($key[$i]) . ' ';    }    echo '<hr />';}/*MyClasspriv (13) => priv_value0 77 121 67 108 97 115 115 0 112 114 105 118*prot (7) => prot_value0 42 0 112 114 111 116pub (3) => pub_value112 117 98MyClasspriv (11) => second_pub_value77 121 67 108 97 115 115 112 114 105 118 */?>The char codes show that the protected keys are prepended with '\0*\0' and private keys are prepended with '\0'.__CLASS__.'\0' so be careful when playing around with this.

If you want to convert a string automatically to float or integer (e.g. "0.234" to float and "123" to int), simply add 0 to the string - PHP will do the rest.e.g.$val = 0 + "1.234";(type of $val is float now)$val = 0 + "123";(type of $val is integer now)

The object casting methods presented here do not take into account the class hierarchy of the class you're trying to cast your object into./**     * Convert an object to a specific class.     * @param object $object     * @param string $class_name The class to cast the object to     * @return object     */    public static function cast($object, $class_name) {        if($object === false) return false;        if(class_exists($class_name)) {            $ser_object     = serialize($object);            $obj_name_len     = strlen(get_class($object));            $start             = $obj_name_len + strlen($obj_name_len) + 6;            $new_object      = 'O:' . strlen($class_name) . ':"' . $class_name . '":';            $new_object     .= substr($ser_object, $start);            $new_object     = unserialize($new_object);            /**             * The new object is of the correct type but             * is not fully initialized throughout its graph.             * To get the full object graph (including parent             * class data, we need to create a new instance of              * the specified class and then assign the new              * properties to it.             */            $graph = new $class_name;            foreach($new_object as $prop => $val) {                $graph->$prop = $val;            }            return $graph;        } else {            throw new CoreException(false, "could not find class $class_name for casting in DB::cast");            return false;        }    }

Printing or echoing a FALSE boolean value or a NULL value results in an empty string:(string)TRUE //returns "1"(string)FALSE //returns ""echo TRUE; //prints "1"echo FALSE; //prints nothing!

There are some shorter and faster (at least on my machine) ways to perform a type cast.<?php$string='12345.678';$float=+$string; $integer=0|$string;$boolean=!!$string;?>

Type casting in expressions is executed first.The casting is assigned to the value, not to the expression result.Examples:<?php$string = "777";var_dump( $string === 777 );            // FALSEvar_dump( (int)  $string === 777 );     // TRUEvar_dump( ( (int) $string ) === 777 );  // TRUEvar_dump( (int) ( $string === 777 ) );  // 0?>

This PHP documentation is very thorough.An observation about comments, maybe they lost sense when become old, and the page changes, so, should be signaled this condition, or add a link to the document version when the comment was made.