Returning values
Values are returned by using the optional return statement. Any type may be returned, including arrays and objects. This causes the function to end its execution immediately and pass control back to the line from which it was called. See return for more information.
Note: If the return is omitted the value
NULLwill be returned.
Use of return
Example #1 Use of return
<?php
function?square($num)
{
????return?$num?*?$num;
}
echo?square(4);???//?outputs?'16'.
?>A function can not return multiple values, but similar results can be obtained by returning an array.
Example #2 Returning an array to get multiple values
<?php
function?small_numbers()
{
????return?array?(0,?1,?2);
}
list?($zero,?$one,?$two)?=?small_numbers();
?>To return a reference from a function, use the reference operator & in both the function declaration and when assigning the returned value to a variable:
Example #3 Returning a reference from a function
<?php
function?&returns_reference()
{
????return?$someref;
}
$newref?=&?returns_reference();
?>For more information on references, please check out References Explained.
Return type declarations
PHP 7 adds support for return type declarations. Similarly to argument type declarations, return type declarations specify the type of the value that will be returned from a function. The same types are available for return type declarations as are available for argument type declarations.
Strict typing also has an effect on return type declarations. In the default weak mode, returned values will be coerced to the correct type if they are not already of that type. In strong mode, the returned value must be of the correct type, otherwise a TypeError will be thrown.
Note: When overriding a parent method, the child's method must match any return type declaration on the parent. If the parent doesn't define a return type, then the child method may do so.
Examples
Example #4 Basic return type declaration
<?php
function?sum($a,?$b):?float?{
????return?$a?+?$b;
}
//?Note?that?a?float?will?be?returned.
var_dump(sum(1,?2));
?>The above example will output:
float(3)Example #5 Strict mode in action
<?php
declare(strict_types=1);
function?sum($a,?$b):?int?{
????return?$a?+?$b;
}
var_dump(sum(1,?2));
var_dump(sum(1,?2.5));
?>The above example will output:
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 5Example #6 Returning an object
<?php
class?C?{}
function?getC():?C?{
????return?new?C;
}
var_dump(getC());
?>The above example will output:
object(C)#1 (0) {
}← Function arguments
Variable functions →
? 1997–2017 The PHP Documentation GroupLicensed under the Creative Commons Attribution License v3.0 or later.
本文档系腾讯云开发者社区成员共同维护，如有问题请联系 cloudcommunity@tencent.com
