Rückgabewerte

Sie können Werte mit dem optionalen Befehl "return" zurückgeben. Es können Variablen jeden Typs zurückgegeben werden, auch Arrays oder Objekte. Dies beendet sofort die Funktion und die Kontrolle wird wieder an die aufrufende Zeile zurückgegeben. Weitere Informationen finden Sie unter return.

Hinweis:

Wird return ausgelassen, dann wird der Wert NULL zurückgegeben.

Einsatz von return

Beispiel #1 Einsatz von return

<?php
function quadrat($zahl)
{
    return 
$zahl $zahl;
}
echo 
quadrat(4);   // gibt '16' aus.

?>

Es ist nicht möglich, mehrere Werte von einer Funktion zurückzugeben. Ein ähnliches Resultat kann man aber durch die Rückgabe eines Arrays erreichen.

Beispiel #2 Rückgabe mehrere Werte in Arrays

<?php
function kleine_zahlen()
{
   return array (
012);
}
list (
$null$eins$zwei) = kleine_zahlen();
?>

Um von einer Funktion eine Referenz zurückzugeben, müssen Sie den Referenz-Operator & sowohl in der Funktionsdeklaration, als auch bei der Zuweisung des zurückgegebenen Wertes verwenden:

Beispiel #3 Rückgabe von Referenzen

<?php
function &returniere_referenz()
{
    return 
$einereferenz;
}

$neuereferenz =& returniere_referenz();
?>

Weitere Informationen über Referenzen finden Sie im Kapitel Referenzen in PHP.

Return type declarations

PHP 7 adds support for return type declarations. Similarly to argument type declarations, return type declarations specify the type of the value that will be returned from a function. The same types are available for return type declarations as are available for argument type declarations.

Strict typing also has an effect on return type declarations. In the default weak mode, returned values will be coerced to the correct type if they are not already of that type. In strong mode, the returned value must be of the correct type, otherwise a TypeError will be thrown.

Hinweis:

When overriding a parent method, the child's method must match any return type declaration on the parent. If the parent doesn't define a return type, then the child method may do so.

Beispiele

Beispiel #4 Basic return type declaration

<?php
function sum($a$b): float {
    return 
$a $b;
}

// Note that a float will be returned.
var_dump(sum(12));
?>

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

float(3)

Beispiel #5 Strict mode in action

<?php
declare(strict_types=1);

function 
sum($a$b): int {
    return 
$a $b;
}

var_dump(sum(12));
var_dump(sum(12.5));
?>

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

int(3)

Fatal error: Uncaught TypeError: Return value of sum() must be of the type integer, float returned in - on line 5 in -:5
Stack trace:
#0 -(9): sum(1, 2.5)
#1 {main}
  thrown in - on line 5

Beispiel #6 Returning an object

<?php
class {}

function 
getC(): {
    return new 
C;
}

var_dump(getC());
?>

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

object(C)#1 (0) {
}
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User Contributed Notes 6 notes

up
13
bgalloway at citycarshare dot org
7 years ago
Be careful about using "do this thing or die()" logic in your return lines.  It doesn't work as you'd expect:

<?php
function myfunc1() {
    return(
'thingy' or die('otherthingy'));
}
function
myfunc2() {
    return
'thingy' or die('otherthingy');
}
function
myfunc3() {
    return(
'thingy') or die('otherthingy');
}
function
myfunc4() {
    return
'thingy' or 'otherthingy';
}
function
myfunc5() {
   
$x = 'thingy' or 'otherthingy'; return $x;
}
echo
myfunc1(). "\n". myfunc2(). "\n". myfunc3(). "\n". myfunc4(). "\n". myfunc5(). "\n";
?>

Only myfunc5() returns 'thingy' - the rest return 1.
up
12
rstaveley at seseit dot com
4 years ago
Developers with a C background may expect pass by reference semantics for arrays. It may be surprising that  pass by value is used for arrays just like scalars. Objects are implicitly passed by reference.

<?php

# (1) Objects are always passed by reference and returned by reference

class Obj {
    public
$x;
}

function
obj_inc_x($obj) {
   
$obj->x++;
    return
$obj;
}

$obj = new Obj();
$obj->x = 1;

$obj2 = obj_inc_x($obj);
obj_inc_x($obj2);

print
$obj->x . ', ' . $obj2->x . "\n";

# (2) Scalars are not passed by reference or returned as such

function scalar_inc_x($x) {
   
$x++;
    return
$x;
}

$x = 1;

$x2 = scalar_inc_x($x);
scalar_inc_x($x2);

print
$x . ', ' . $x2 . "\n";

# (3) You have to force pass by reference and return by reference on scalars

function &scalar_ref_inc_x(&$x) {
   
$x++;
    return
$x;
}

$x = 1;

$x2 =& scalar_ref_inc_x($x);    # Need reference here as well as the function sig
scalar_ref_inc_x($x2);

print
$x . ', ' . $x2 . "\n";

# (4) Arrays use pass by value sematics just like scalars

function array_inc_x($array) {
   
$array{'x'}++;
    return
$array;
}

$array = array();
$array['x'] = 1;

$array2 = array_inc_x($array);
array_inc_x($array2);

print
$array['x'] . ', ' . $array2['x'] . "\n";

# (5) You have to force pass by reference and return by reference on arrays

function &array_ref_inc_x(&$array) {
   
$array{'x'}++;
    return
$array;
}

$array = array();
$array['x'] = 1;

$array2 =& array_ref_inc_x($array); # Need reference here as well as the function sig
array_ref_inc_x($array2);

print
$array['x'] . ', ' . $array2['x'] . "\n";
up
6
nick at itomic.com
12 years ago
Functions which return references, may return a NULL value. This is inconsistent with the fact that function parameters passed by reference can't be passed as NULL (or in fact anything which isnt a variable).

i.e.

<?php

function &testRet()
{
    return
NULL;
}

if (
testRet() === NULL)
{
    echo
"NULL";
}
?>

parses fine and echoes NULL
up
3
ian at NO_SPAM dot verteron dot net
12 years ago
In reference to the poster above, an additional (better?) way to return multiple values from a function is to use list(). For example:

function fn($a, $b)
{
   # complex stuff

   return array(
      $a * $b,
      $a + $b,
   );
}

list($product, $sum) = fn(3, 4);

echo $product; # prints 12
echo $sum; # prints 7
up
-5
Anonymous
5 years ago
As of at least PHP 5.3, a function or class method returning an object acts like an object.

<?php

class A {
    function
test() {
        echo
"Yay!";
        }
    }

function
get_obj() {
    return new
A();
    }

get_obj()->test();  // "Yay!"

?>

Sorry, still doesn't work with arrays.  Ie <?php echo get_array()[1]; ?> fails.
up
-23
ahmad at myandmyhost dot comze dot com
1 year ago
we can return array using foreach
<?php
function my_func2()
{
    return array(
"Name"=>"Ahmad Sayeed","Email"=>"ahmad@gmail.com");
   
}
$ar = my_func2();
foreach(
$ar as $key=>$value)
{echo
$key." , ".$value,"<br />";}

?>
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