问题
Is it possible to have a function with 2 returns like this:
function test($testvar)
{
// do something
return $var1;
return $var2;
}
If so, how would I be able to get each return separately?
回答1:
There is no way of returning 2 variables. Although, you can propagate an array and return it; create a conditional to return a dynamic variable, etc.
For instance, this function would return $var2
function wtf($blahblah = true) {
$var1 = "ONe";
$var2 = "tWo";
if($blahblah === true) {
return $var2;
}
return $var1;
}
In application:
echo wtf();
//would echo: tWo
echo wtf("not true, this is false");
//would echo: ONe
If you wanted them both, you could modify the function a bit
function wtf($blahblah = true) {
$var1 = "ONe";
$var2 = "tWo";
if($blahblah === true) {
return $var2;
}
if($blahblah == "both") {
return array($var1, $var2);
}
return $var1;
}
echo wtf("both")[0]
//would echo: ONe
echo wtf("both")[1]
//would echo: tWo
list($first, $second) = wtf("both")
// value of $first would be $var1, value of $second would be $var2
回答2:
Technically, you can't return more than one value. However, there are multiple ways to work around that limitation. The way that acts most like returning multiple values, is with the list keyword:
function getXYZ()
{
return array(4,5,6);
}
list($x,$y,$z) = getXYZ();
// Afterwards: $x == 4 && $y == 5 && $z == 6
// (This will hold for all samples unless otherwise noted)
Technically, you're returning an array and using list to store the elements of that array in different values instead of storing the actual array. Using this technique will make it feel most like returning multiple values.
The list solution is a rather php-specific one. There are a few languages with similar structures, but more languages that don't. There's another way that's commonly used to "return" multiple values and it's available in just about every language (in one way or another). However, this method will look quite different so may need some getting used to.
// note that I named the arguments $a, $b and $c to show that
// they don't need to be named $x, $y and $z
function getXYZ(&$a, &$b, &$c)
{
$a = 4;
$b = 5;
$c = 6;
}
getXYZ($x, $y, $z);
This technique is also used in some functions defined by php itself (e.g. $count in str_replace, $matches in preg_match). This might feel quite different from returning multiple values, but it is worth at least knowing about.
A third method is to use an object to hold the different values you need. This is more typing, so it's not used quite as often as the two methods above. It may make sense to use this, though, when using the same set of variables in a number of places (or of course, working in a language that doesn't support the above methods or allows you to do this without extra typing).
class MyXYZ
{
public $x;
public $y;
public $z;
}
function getXYZ()
{
$out = new MyXYZ();
$out->x = 4;
$out->y = 5;
$out->z = 6;
return $out;
}
$xyz = getXYZ();
$x = $xyz->x;
$y = $xyz->y;
$z = $xyz->z;
The above methods sum up the main ways of returning multiple values from a function. However, there are variations on these methods. The most interesting variations to look at, are those in which you are actually returning an array, simply because there's so much you can do with arrays in PHP.
First, we can simply return an array and not treat it as anything but an array:
function getXYZ()
{
return array(1,2,3);
}
$array = getXYZ();
$x = $array[1];
$y = $array[2];
$z = $array[3];
The most interesting part about the code above is that the code inside the function is the same as in the very first example I provided; only the code calling the function changed. This means that it's up to the one calling the function how to treat the result the function returns.
Alternatively, one could use an associative array:
function getXYZ()
{
return array('x' => 4,
'y' => 5,
'z' => 6);
}
$array = getXYZ();
$x = $array['x'];
$y = $array['y'];
$z = $array['z'];
Php does have the compact function that allows you to do same as above but while writing less code. (Well, the sample won't have less code, but a real world application probably would.) However, I think the amount of typing saving is minimal and it makes the code harder to read, so I wouldn't do it myself. Nevertheless, here's a sample:
function getXYZ()
{
$x = 4;
$y = 5;
$z = 6;
return compact('x', 'y', 'z');
}
$array = getXYZ();
$x = $array['x'];
$y = $array['y'];
$z = $array['z'];
It should be noted that while compact does have a counterpart in extract that could be used in the calling code here, but since it's a bad idea to use it (especially for something as simple as this) I won't even give a sample for it. The problem is that it will do "magic" and create variables for you, while you can't see which variables are created without going to other parts of the code.
Finally, I would like to mention that list doesn't really play well with associative array. The following will do what you expect:
function getXYZ()
{
return array('x' => 4,
'y' => 5,
'z' => 6);
}
$array = getXYZ();
list($x, $y, $z) = getXYZ();
However, the following will do something different:
function getXYZ()
{
return array('x' => 4,
'z' => 6,
'y' => 5);
}
$array = getXYZ();
list($x, $y, $z) = getXYZ();
// Pay attention: $y == 6 && $z == 5
If you used list with an associative array, and someone else has to change the code in the called function in the future (which may happen just about any situation) it may suddenly break, so I would recommend against combining list with associative arrays.
回答3:
In your example, the second return will never happen - the first return is the last thing PHP will run. If you need to return multiple values, return an array:
function test($testvar) {
return array($var1, $var2);
}
$result = test($testvar);
echo $result[0]; // $var1
echo $result[1]; // $var2
回答4:
Since Php 7.1 we have proper destructuring for lists. Thereby you can do things like this:
$test = [1,2,3,4];
[$a, $b, $c, $d] = $test;
echo($a);
> 1
echo($d);
> 4
In a function this would look like this:
function multiple_return() {
return ['this', 'is', 'a', 'test'];
}
[$first, $second, $third, $fourth] = multiple_return();
echo($first);
> this
echo($fourth);
> test
Destructuring is a very powerful tool. It's capable of destructuring key=>value pairs as well
["a" => $a, "b" => $b, "c" => $c] = ["a" => 1, "b" => 2, "c" => 3];
Take a look at the new feature page: http://php.net/manual/de/migration71.new-features.php
回答5:
In PHP 5.5 there is also a new concept: generators, where you can yield multiple values from a function:
function hasMultipleValues() {
yield "value1";
yield "value2";
}
$values = hasMultipleValues();
foreach ($values as $val) {
// $val will first be "value1" then "value2"
}
回答6:
Or you can pass by reference:
function byRef($x, &$a, &$b)
{
$a = 10 * $x;
$b = 100 * $x;
}
$a = 0;
$b = 0;
byRef(10, $a, $b);
echo $a . "\n";
echo $b;
This would output
100
1000
回答7:
I know that I am pretty late, but there is a nice and simple solution for this problem.
It's possible to return multiple values at once using destructuring.
function test()
{
return [ 'model' => 'someValue' , 'data' => 'someothervalue'];
}
Now you can use this
$result = test();
extract($result);
extract creates a variable for each member in the array, named after that member. You can therefore now access $model and $data
回答8:
You can return multiple arrays and scalars from a function
function x()
{
$a=array("a","b","c");
$b=array("e","f");
return array('x',$a,$b);
}
list ($m,$n,$o)=x();
echo $m."\n";
print_r($n);
print_r($o);
回答9:
Its not possible have two return statement. However it doesn't throw error but when function is called you will receive only first return statement value. We can use return of array to get multiple values in return. For Example:
function test($testvar)
{
// do something
//just assigning a string for example, we can assign any operation result
$var1 = "result1";
$var2 = "result2";
return array('value1' => $var1, 'value2' => $var2);
}
回答10:
yes, you can use an object :-)
but the simplest way is to return an array:
return array('value1','value2','value3','...');
回答11:
Functions, by definition, only return one value.
However, as you assumed, that value can be an array.
So you can certainly do something like:
<?PHP
function myfunc($a,$b){
return array('foo'=>$a,'bar'=>$b);
}
print_r(myfunc('baz','bork'));
That said, it's worth taking a moment and thinking about whatever you're trying to solve. While returning a complex result value (like an array, or an object) is perfectly valid, if you're thinking is that "I want to return two values", you might be designing poorly. Without more detail in your question, it's hard to say, but it never hurts to stop and think twice.
回答12:
I have implement like this for multiple return value PHP function. be nice with your code. thank you.
<?php
function multi_retun($aa)
{
return array(1,3,$aa);
}
list($one,$two,$three)=multi_retun(55);
echo $one;
echo $two;
echo $three;
?>
回答13:
The answer that's given the green tick above is actually incorrect. You can return multiple values in PHP, if you return an array. See the following code for an example:
<?php
function small_numbers()
{
return array (0, 1, 2);
}
list ($zero, $one, $two) = small_numbers();
This code is actually copied from the following page on PHP's website: http://php.net/manual/en/functions.returning-values.php I've also used the same sort of code many times myself, so can confirm that it's good and that it works.
回答14:
yes and no, you can't return more than one variable / object, but as you suggest, you can put them into an array and return that, there is no limit to the nesting of arrays so you can just package them up that way to return
回答15:
Functions in PHP can return only one variable. you could use variables with global scope, you can return array, or you can pass variable by reference to the function and than change value,.. but all of that will decrease readability of your code. I would suggest that you look into the classes.
回答16:
Thought I would expand on a few of the responses from above....
class nameCheck{
public $name;
public function __construct(){
$this->name = $name;
}
function firstName(){
// If a name has been entered..
if(!empty($this->name)){
$name = $this->name;
$errflag = false;
// Return a array with both the name and errflag
return array($name, $errflag);
// If its empty..
}else if(empty($this->name)){
$errmsg = 'Please enter a name.';
$errflag = true;
// Return both the Error message and Flag
return array($errmsg, $errflag);
}
}
}
if($_POST['submit']){
$a = new nameCheck;
$a->name = $_POST['name'];
// Assign a list of variables from the firstName function
list($name, $err) = $a->firstName();
// Display the values..
echo 'Name: ' . $name;
echo 'Errflag: ' . $err;
}
?>
<form method="post" action="<?php $_SERVER['PHP_SELF']; ?>" >
<input name="name" />
<input type="submit" name="submit" value="submit" />
</form>
This will give you a input field and a submit button once submitted, if the name input field is empty it will return the error flag and a message. If the name field has a value it will return the value/name and a error flag of 0 for false = no errors. Hope this helps!
回答17:
Some might prefer returning multiple values as object:
function test() {
$object = new stdClass();
$object->x = 'value 1';
$object->y = 'value 2';
return $object;
}
And call it like this:
echo test()->x;
Or:
$test = test();
echo $test->y;
回答18:
You can always only return one variable which might be an array. But You can change global variables from inside the function. That is most of the time not very good style, but it works. In classes you usually change class varbiables from within functions without returning them.
回答19:
The answer is no. When the parser reaches the first return statement, it will direct control back to the calling function - your second return statement will never be executed.
回答20:
Add all variables in an array and then finally return the array.
function test($testvar)
{
// do something
return array("var1" => $var1, "var2" => @var2);
}
And then
$myTest = test($myTestVar);
//$myTest["var1"] and $myTest["var2"] will be usable
回答21:
Best Practice is to put your returned variables into array and then use list() to assign array values to variables.
<?php
function add_subt($val1, $val2) {
$add = $val1 + $val2;
$subt = $val1 - $val2;
return array($add, $subt);
}
list($add_result, $subt_result) = add_subt(20, 7);
echo "Add: " . $add_result . '<br />';
echo "Subtract: " . $subt_result . '<br />';
?>
回答22:
I think eliego has explained the answer clearly. But if you want to return both values, put them into a array and return it.
function test($testvar)
{
// do something
return array('var1'=>$var1,'var2'=>$var2);
//defining a key would be better some times
}
//to access return values
$returned_values = test($testvar);
echo $returned_values['var1'];
echo $returned_values['var2'];
回答23:
For PHP 7.1 <= you can use new syntax (instead list function):
/**
* @return array [foo, bar]
*/
function getFooAndBar(): array {
return ['foo', 'bar'];
}
[$foo, $bar] = getFooAndBar();
print 'Hello '. $foo .' and '. $bar;
It's ok for me if you want to return 2-3 variables, otherwise you should use object with desired properties.
回答24:
Languages which allow multiple returns usually just convert the multiple values into a data structure.
For example, in python you can return multiple values, however they're actually just being returned as 1 tuple.
So you can return multiple values in PHP by just creating a simple array and returning that.
回答25:
You can get values of two or more variables by setting them by reference
function t(&$a, &$b) {
$a = 1;
$b = 2;
}
t($a,$b);
echo $a . ' ' . $b;
output:
1 2
回答26:
<?php
function foo(){
$you = 5;
$me = 10;
return $you;
return $me;
}
echo foo();
//output is just 5 alone so we cant get second one it only retuns first one so better go with array
function goo(){
$you = 5;
$me = 10;
return $you_and_me = array($you,$me);
}
var_dump(goo()); // var_dump result is array(2) { [0]=> int(5) [1]=> int(10) } i think thats fine enough
?>
回答27:
Does php still use "out parameters"? If so, you can use the syntax to modify one or more of the parameters going in to your function then, you would then be free to use the modified variable after your function returns.
回答28:
This is the easiest way to it
public function selectAllUsersByRole($userRole, $selector){
$this->userRole = $userLevel;
$this->selector = $selector;
$sql = "SELECT * FROM users WHERE role <= ? AND del_stat = 0";
$stm = $this->connect()->prepare($sql);// connect function in Dbh connect to database file
$stm->execute([$this->userRole]);//this is php7, use array($this->userRole) for php5
$usersIdArray = array();
$usersFNameArray = array();
$usersLNameArray = array();
if($stm->rowCount()){
while($row = $stm->fetch()){
array_push($usersIdArray, $row['id']);
array_push($usersFNameArray, $row['f_name']);
array_push($usersLNameArray, $row['l_name']);
// you cane return only $row['id'] or f_name or .....
//I used the array cause its most using
}
}
if($this->selector == 1) {
return $usersIdArray;
}elseif($this->selector == 2) {
return $usersFNameArray;
}elseif($this->selector == 3) {
return $usersLNameArray;
}
}
How to call this function?
$idData= $selectAllUsers->selectAllUsersByLevel($userRole,0);
print_r($idData);
$idFName= $selectAllUsers->selectAllUsersByLevel($userRole,1);
print_r($idFname);
That's it, very rasy
回答29:
$var1 = 0;
$var2 = 0;
function test($testvar, &$var1 , &$var2)
{
$var1 = 1;
$var2 = 2;
return;
}
test("", $var1, $var2);
// var1 = 1, var2 = 2
It's not a good way but I think we can set 2 variables in a function at same time
回答30:
I had a similar problem - so I tried around and googled a bit (finding this thread). After 5 minutes of try and error I found out that you can simply use "AND" to return two (maybe more - not tested yet) in one line of return.
My code:
function get_id(){
global $b_id, $f_id;
// stuff happens
return $b_id AND $f_id;
}
//later in the code:
get_id();
var_dump($b_id);
var_dump($f_id); // tested output by var_dump
it works. I got both the values I expected to get/should get. I hope I could help anybody reading this thread :)
来源：https://stackoverflow.com/questions/3451906/multiple-returns-from-function