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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.

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 von 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.

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User Contributed Notes 6 notes

up
7
rstaveley at seseit dot com
3 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
Anonymous
4 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
5
bgalloway at citycarshare dot org
6 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
2
nick at itomic.com
11 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
2
ian at NO_SPAM dot verteron dot net
11 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
-1
ahmad at myandmyhost dot comze dot com
6 months 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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