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If called from within a function, the return()
statement immediately ends execution of the current function, and
returns its argument as the value of the function
call. return() will also end the execution of
an eval() statement or script file.
If called from the global scope, then execution of the current
script file is ended. If the current script file was
include()ed or require()ed,
then control is passed back to the calling file. Furthermore, if
the current script file was include()ed, then
the value given to return() will be returned as
the value of the include() call. If
return() is called from within the main script
file, then script execution ends. If the current script file was
named by the auto_prepend_file or auto_append_file
configuration options in php.ini,
then that script file's execution is ended.
For more information, see Returning values.
Замечание:
Note that since return() is a language
construct and not a function, the parentheses surrounding its
arguments are not required. It is common to leave them out, and you
actually should do so as PHP has less work to do in this case.
Замечание:
You should never use parentheses around your return
variable when returning by reference, as this will not work. You can
only return variables by reference, not the result of a statement. If
you use return ($a); then you're not returning a
variable, but the result of the expression ($a)
(which is, of course, the value of $a).
mr dot xanadu at gmail dot com
12-Oct-2007 01:56
I was wondering what was quicker:
- return a boolean as soon I know it's value ('direct') or
- save the boolean in a variable and return it at the function's end.
<?php
$times = 50000;
function return_direct ($boolean)
{
if ($boolean == true)
{
return true;
}
return false;
}
function return_indirect ($boolean)
{
$return = false;
if ($boolean == true)
{
$return = true;
}
return $return;
}
$time_start = microtime(true);
for ($i = 1; $i <= $times; $i++)
{
return_direct(true);
}
$time_end = microtime(true);
$time_direct_true = $time_end - $time_start;
$time_start = microtime(true);
for ($i = 1; $i <= $times; $i++)
{
return_direct(false);
}
$time_end = microtime(true);
$time_direct_false = $time_end - $time_start;
$time_start = microtime(true);
for ($i = 1; $i <= $times; $i++)
{
return_indirect(true);
}
$time_end = microtime(true);
$time_indirect_true = $time_end - $time_start;
$time_start = microtime(true);
for ($i = 1; $i <= $times; $i++)
{
return_indirect(false);
}
$time_end = microtime(true);
$time_indirect_false = $time_end - $time_start;
echo "<pre>";
echo "direct true\t" . $time_direct_true;
echo "\ndirect false\t" . $time_direct_false;
echo "\nindirect true\t" . $time_indirect_true;
echo "\nindirect false\t" . $time_indirect_false;
echo "<pre>";
?>
Representative results:
direct true 0.163973093033
direct false 0.1270840168
indirect true 0.0733940601349
indirect false 0.0742440223694
Conclusion: saving the result in a variable appears to be faster. (Please note that my test functions are very simple, maybe it's slower on longer functions)
Spacecat
24-Jul-2007 06:13
regardez this code:
print pewt( "hello!" );
function pewt( $arg )
{
include( "some_code.inc" );
}
some_code.inc:
return strtoupper( $arg );
.. after much hair pulling, discovered why nothing was being returned by the "some_code.inc" code in the function .. the return simply returns the result TO the function (giving the include function a value), not to the CALLING (print pewt). This works:
print pewt( "hello!" );
function pewt( $arg )
{
return include( "some_code.inc" );
}
So, RETURN works relative to block it is executed within.
warhog at warhog dot net
18-Dec-2005 12:28
for those of you who think that using return in a script is the same as using exit note that: using return just exits the execution of the current script, exit the whole execution.
look at that example:
a.php
<?php
include("b.php");
echo "a";
?>
b.php
<?php
echo "b";
return;
?>
(executing a.php:) will echo "ba".
whereas (b.php modified):
a.php
<?php
include("b.php");
echo "a";
?>
b.php
<?php
echo "b";
exit;
?>
(executing a.php:) will echo "b".
mike at uwmike dot com
06-Dec-2005 09:25
If you have a class file that's getting out of control, you can set it up like so:
<?php
class myClass {
function do_this($a, $b) { return require(myClass_do_this.php); }
function do_that($a, $b, $c) { return require(myClass_do_that.php); }
}
?>
Might not be for everyone, but it's workable, readable, and keeps the source files shorter.
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