Related
I need to be able to call a function, but the function name is stored in a variable, is this possible? e.g:
function foo ()
{
//code here
}
function bar ()
{
//code here
}
$functionName = "foo";
// I need to call the function based on what is $functionName
$functionName() or call_user_func($functionName)
My favorite version is the inline version:
${"variableName"} = 12;
$className->{"propertyName"};
$className->{"methodName"}();
StaticClass::${"propertyName"};
StaticClass::{"methodName"}();
You can place variables or expressions inside the brackets too!
Solution: Use PHP7
Note: For a summarized version, see TL;DR at the end of the answer.
Old Methods
Update: One of the old methods explained here has been removed. Refer to other answers for explanation on other methods, it isn't covered here. By the way, if this answer doesn't help you, you should return upgrading your stuff. PHP 5.6 support has ended in January 2019 (now even PHP 7.2 and 7.3 are not being supported). See supported versions for more information.
As others mentioned, in PHP5 (and also in newer versions like PHP7) we could use variables as function names, use call_user_func() and call_user_func_array(), etc.
New Methods
As of PHP7, there are new ways introduced:
Note: Everything inside <something> brackets means one or more expressions to form something, e.g. <function_name> means expressions forming a function name.
Dynamic Function Call: Function Name On-the-fly
We can form a function name inside parentheses in just one go:
(<function_name>)(arguments);
For example:
function something(): string
{
return "something";
}
$bar = "some_thing";
(str_replace("_", "", $bar))(); // something
// Possible, too; but generally, not recommended, because makes your
// code more complicated
(str_replace("_", "", $bar))()();
Note: Although removing the parentheses around str_replace() is not an error, putting parentheses makes code more readable. However, you cannot do that sometimes, e.g. while using . operator. To be consistent, I recommend you to put the parentheses always.
Dynamic Function Call: Callable Property
A useful example would be in the context of objects: If you have stored a callable in a property, you have to call it this way:
($object->{<property_name>})();
As a simple example:
// Suppose we're in a class method context
($this->eventHandler)();
Obviously, calling it as $this->eventHandler() is plain wrong: By that you mean calling a method named eventHandler.
Dynamic Method Call: Method Name On-the-fly
Just like dynamic function calls, we can do the same way with method calls, surrounded by curly braces instead of parentheses (for extra forms, navigate to TL;DR section):
$object->{<method_name>}(arguments);
$object::{<method_name>}(arguments);
See it in an example:
class Foo
{
public function another(): string
{
return "something";
}
}
$bar = "another thing";
(new Something())->{explode(" ", $bar)[0]}(); // something
Dynamic Method Call: The Array Syntax
A more elegant way added in PHP7 is the following:
[<object>, <method_name>](arguments);
[<class_name>, <method_name>](arguments); // Static calls only
As an example:
class Foo
{
public function nonStaticCall()
{
echo "Non-static call";
}
public static function staticCall()
{
echo "Static call";
}
}
$x = new X();
[$x, "non" . "StaticCall"](); // Non-static call
[$x, "static" . "Call"](); // Static call
Note: The benefit of using this method over the previous one is that, you don't care about the call type (i.e. whether it's static or not).
Note: If you care about performance (and micro-optimizations), don't use this method. As I tested, this method is really slower than other methods (more than 10 times).
Extra Example: Using Anonymous Classes
Making things a bit complicated, you could use a combination of anonymous classes and the features above:
$bar = "SomeThing";
echo (new class {
public function something()
{
return 512;
}
})->{strtolower($bar)}(); // 512
TL;DR (Conclusion)
Generally, in PHP7, using the following forms are all possible:
// Everything inside `<something>` brackets means one or more expressions
// to form something
// Dynamic function call via function name
(<function_name>)(arguments);
// Dynamic function call on a callable property
($object->{<property_name>})(arguments);
// Dynamic method call on an object
$object->{<method_name>}(arguments);
$object::{<method_name>}(arguments);
// Dynamic method call on a dynamically-generated object
(<object>)->{<method_name>}(arguments);
(<object>)::{<method_name>}(arguments);
// Dynamic method call, statically
ClassName::{<method_name>}(arguments);
(<class_name>)::{<method_name>}(arguments);
// Dynamic method call, array-like (no different between static
// and non-static calls
[<object>, <method_name>](arguments);
// Dynamic method call, array-like, statically
[<class_name>, <method_name>](arguments);
Special thanks to this PHP talk.
Yes, it is possible:
function foo($msg) {
echo $msg."<br />";
}
$var1 = "foo";
$var1("testing 1,2,3");
Source: http://www.onlamp.com/pub/a/php/2001/05/17/php_foundations.html?page=2
As already mentioned, there are a few ways to achieve this with possibly the safest method being call_user_func() or if you must you can also go down the route of $function_name(). It is possible to pass arguments using both of these methods as so
$function_name = 'foobar';
$function_name(arg1, arg2);
call_user_func_array($function_name, array(arg1, arg2));
If the function you are calling belongs to an object you can still use either of these
$object->$function_name(arg1, arg2);
call_user_func_array(array($object, $function_name), array(arg1, arg2));
However if you are going to use the $function_name() method it may be a good idea to test for the existence of the function if the name is in any way dynamic
if(method_exists($object, $function_name))
{
$object->$function_name(arg1, arg2);
}
A few years late, but this is the best manner now imho:
$x = (new ReflectionFunction("foo"))->getClosure();
$x();
In case someone else is brought here by google because they were trying to use a variable for a method within a class, the below is a code sample which will actually work. None of the above worked for my situation. The key difference is the & in the declaration of $c = & new... and &$c being passed in call_user_func.
My specific case is when implementing someone's code having to do with colors and two member methods lighten() and darken() from the csscolor.php class. For whatever reason, I wanted to have the same code be able to call lighten or darken rather than select it out with logic. This may be the result of my stubbornness to not just use if-else or to change the code calling this method.
$lightdark="lighten"; // or optionally can be darken
$color="fcc"; // a hex color
$percent=0.15;
include_once("csscolor.php");
$c = & new CSS_Color($color);
$rtn=call_user_func( array(&$c,$lightdark),$color,$percent);
Note that trying anything with $c->{...} didn't work. Upon perusing the reader-contributed content at the bottom of php.net's page on call_user_func, I was able to piece together the above. Also, note that $params as an array didn't work for me:
// This doesn't work:
$params=Array($color,$percent);
$rtn=call_user_func( array(&$c,$lightdark),$params);
This above attempt would give a warning about the method expecting a 2nd argument (percent).
For the sake of completeness, you can also use eval():
$functionName = "foo()";
eval($functionName);
However, call_user_func() is the proper way.
Dynamic function names and namespaces
Just to add a point about dynamic function names when using namespaces.
If you're using namespaces, the following won't work except if your function is in the global namespace:
namespace greetings;
function hello()
{
// do something
}
$myvar = "hello";
$myvar(); // interpreted as "\hello();"
What to do?
You have to use call_user_func() instead:
// if hello() is in the current namespace
call_user_func(__NAMESPACE__.'\\'.$myvar);
// if hello() is in another namespace
call_user_func('mynamespace\\'.$myvar);
Complementing the answer of #Chris K if you want to call an object's method, you can call it using a single variable with the help of a closure:
function get_method($object, $method){
return function() use($object, $method){
$args = func_get_args();
return call_user_func_array(array($object, $method), $args);
};
}
class test{
function echo_this($text){
echo $text;
}
}
$test = new test();
$echo = get_method($test, 'echo_this');
$echo('Hello'); //Output is "Hello"
I posted another example here
Use the call_user_func function.
What I learnt from this question and the answers. Thanks all!
Let say I have these variables and functions:
$functionName1 = "sayHello";
$functionName2 = "sayHelloTo";
$functionName3 = "saySomethingTo";
$friend = "John";
$datas = array(
"something"=>"how are you?",
"to"=>"Sarah"
);
function sayHello()
{
echo "Hello!";
}
function sayHelloTo($to)
{
echo "Dear $to, hello!";
}
function saySomethingTo($something, $to)
{
echo "Dear $to, $something";
}
To call function without arguments
// Calling sayHello()
call_user_func($functionName1);
Hello!
To call function with 1 argument
// Calling sayHelloTo("John")
call_user_func($functionName2, $friend);
Dear John, hello!
To call function with 1 or more arguments
This will be useful if you are dynamically calling your functions and each function have different number of arguments. This is my case that I have been looking for (and solved). call_user_func_array is the key
// You can add your arguments
// 1. statically by hard-code,
$arguments[0] = "how are you?"; // my $something
$arguments[1] = "Sarah"; // my $to
// 2. OR dynamically using foreach
$arguments = NULL;
foreach($datas as $data)
{
$arguments[] = $data;
}
// Calling saySomethingTo("how are you?", "Sarah")
call_user_func_array($functionName3, $arguments);
Dear Sarah, how are you?
Yay bye!
If you were in a object context trying to call a function dynamically please try something like this code bellow:
$this->{$variable}();
Following code can help to write dynamic function in PHP.
now the function name can be dynamically change by variable '$current_page'.
$current_page = 'home_page';
$function = #${$current_page . '_page_versions'};
$function = function() {
echo 'current page';
};
$function();
The easiest way to call a function safely using the name stored in a variable is,
//I want to call method deploy that is stored in functionname
$functionname = 'deploy';
$retVal = {$functionname}('parameters');
I have used like below to create migration tables in Laravel dynamically,
foreach(App\Test::$columns as $name => $column){
$table->{$column[0]}($name);
}
Considering some of the excellent answers given here, sometimes you need to be precise.
For example.
if a function has a return value eg (boolean,array,string,int,float
e.t.c).
if the function has no return value check
if the function exists
Let's look at its credit to some of the answers given.
Class Cars{
function carMake(){
return 'Toyota';
}
function carMakeYear(){
return 2020;
}
function estimatedPriceInDollar{
return 1500.89;
}
function colorList(){
return array("Black","Gold","Silver","Blue");
}
function carUsage(){
return array("Private","Commercial","Government");
}
function getCar(){
echo "Toyota Venza 2020 model private estimated price is 1500 USD";
}
}
We want to check if method exists and call it dynamically.
$method = "color List";
$class = new Cars();
//If the function have return value;
$arrayColor = method_exists($class, str_replace(' ', "", $method)) ? call_user_func(array($this, $obj)) : [];
//If the function have no return value e.g echo,die,print e.t.c
$method = "get Car";
if(method_exists($class, str_replace(' ', "", $method))){
call_user_func(array($class, $method))
}
Thanks
One unconventional approach, that came to my mind is, unless you are generating the whole code through some super ultra autonomous AI which writes itself, there are high chances that the functions which you want to "dynamically" call, are already defined in your code base. So why not just check for the string and do the infamous ifelse dance to summon the ...you get my point.
eg.
if($functionName == 'foo'){
foo();
} else if($functionName == 'bar'){
bar();
}
Even switch-case can be used if you don't like the bland taste of ifelse ladder.
I understand that there are cases where the "dynamically calling the function" would be an absolute necessity (Like some recursive logic which modifies itself). But most of the everyday trivial use-cases can just be dodged.
It weeds out a lot of uncertainty from your application, while giving you a chance to execute a fallback function if the string doesn't match any of the available functions' definition. IMHO.
I dont know why u have to use that, doesnt sound so good to me at all, but if there are only a small amount of functions, you could use a if/elseif construct.
I dont know if a direct solution is possible.
something like
$foo = "bar";
$test = "foo";
echo $$test;
should return bar, you can try around but i dont think this will work for functions
Class Base {
function processAction($methodName, $params) {
call_user_func_array(array($this,$methodName), $params);
}
}
class Child1 extends Base {
function getData($param1, $param2, $timestamp) {}
}
class Child2 extends Base {
function getInfo($param1) {}
}
I will be calling in the processAction to call into the methods of the child classes.
I have multiple child classes with different method signatures. I want to pass in $timestamp to some of them. The issue is, I do not want to make timestamp an optional parameter for methods that do not require. I want to be able to pass in $timestamp to only relevant methods. How will i do that ?
EDIT
I plan to add $timestamp just before cal_user_func_array() call.
$array_push($params, $timestamp);
But that would mean, that every method would expect $timestamp, which i don't want.
As mentioned in my comments, php only cares that you pass enough arguments to match the number of parameters declared. If you set a default value for a parameter, then it doesn't even care about that.
The function will "ignore" any extra parameters you pass to it, in the sense that php doesn't care and won't throw an error. However, note that any extra arguments passed to your function are exposed to the function. For example, you can use func_get_args() to get an array of values passed to the function, regardless of how many parameters were actually declared.
Example 1:
function myFunc() {}
myFunc(); // good
myfunc('foo'); // good
Example 2:
function myFunc($p1) {}
myFunc(); // bad
myfunc('foo'); // good
myfunc('foo','bar'); // good
Example 3:
function myFunc($p1='') {}
myFunc(); // good
myfunc('foo'); // good
Example 4:
function myFunc() {
print_r(func_get_args());
}
myFunc('foo','bar');
/*output:
Array
(
[0] => foo
[1] => bar
)
*/
Now let's say for shits and grins you do in fact want to enforce only passing relevant args to the methods. There are several ways to enforce this, depending on what you ultimately want to do. If you want to make it to where named arguments are passed, you're going to have to restructure your code to accept an associative array of params. Then you can write some conditions to figure out which ones were passed and pass them along or throw an exception or whatever. If you only care about number of arguments, it will be easier, because you can more or less leave your code structure as-is, and count the number of params passed.
Now, as far as figuring out how many parameters a given method has. Here is an example using the Reflection class to point you in the right direction:
Class Base {
function processAction($methodName, $params) {
// setup a reflection method object
$refMeth = new ReflectionMethod(get_class($this).'::'.$methodName);
// get a list of the parameter names, if you want to go the 'named' route
foreach($refMeth->getParameters() as $param) {
$sigParams[] = $param->getName();
}
// echo out as example
print_r($sigParams);
// or just get the number of params for the method
echo $refMeth->getNumberOfParameters();
call_user_func_array(array($this,$methodName), $params);
}
}
class Child1 extends Base {
function getData($param1, $param2, $timestamp) {}
}
class Child2 extends Base {
function getInfo($param1) {}
}
// example:
$x = new Child1();
$x->processAction('getData',array('foo','bar','12345'));
/*output
Array
(
[0] => param1
[1] => param2
[2] => timestamp
)
3
*/
So there's an example of how to find out the expected params for a given method, so you can compare to passed args and explicitly call call_user_func_array with only relevant values so that the extras (even though php would 'ignore' them) won't even be exposed, or throw an exception instead, etc..
I came across plenty of examples of method chaining in PHP, but couldn't find anything about this one, so I'm asking for help you guys;)
My problem is - can I in some way find out if the method in chain is the last one? In most cases people are using some sort of final method (execute, send,..) to tell when the chain ends and return the corresponding result. But I wonder if there is some hidden magic method or technique than can check all the methods in chain and detect if there is no next method?
Without final method it works fine for strings (in the very simple example), but not if I want to return array.
Here is my snippet :
class Chain {
private $strArray;
function __call($name, $args) {
$this->strArray[] = $args[0];
return $this;
}
function __toString() {
return implode('-', $this->strArray);
}
}
// example 1
$c = new Chain();
$x = $c->foo('hi')->bar('stack'); // need array('hi', 'stack')
// example 2
$c = new Chain();
$x = $c->foo('hi')->bar('stack')->foobar('overflow'); // need array('hi', 'stack', 'overflow')
// example 3
$c = new Chain();
echo $c->foo('hi')->foobar('overflow'); // prints 'hi-overflow'
// example 4
$c = new Chain();
echo $c->foo('hi')->bar('stack')->foobar('overflow'); // prints 'hi-stack-overflow'
You see, when I want to print the result of chain, I can modify the result in the __toString method, but what if I need an array (example 1, 2)? Is there any way to achieve that without calling some additional "final" method?
Thanks a lot for help and let me know if you need more info.
EDIT: After feedback from #bandi I tried to extend ArrayObject like this.
class Chain extends ArrayObject {
function __call($name, $args) {
$this->append($args[0]);
return $this;
}
function __toString() {
return implode('-', $this->getIterator()->getArrayCopy());
}
}
// returned ref. to object, works fine in loop or accessing offset
$obj = new Chain;
$x = $obj->foo('hi')->bar('stack')->foobar('overflow'); // need array('hi', 'stack', 'overflow')
foreach ($x as $y) {
echo $y, "\n";
}
var_dump($x[0], $x[1], $x[2]);
// returned String
$c = new Chain;
echo $c->foo('hi')->foobar('overflow'); // prints 'hi-overflow'
It does what I wanted, however I don't feel so good about the $this->getIterator()->getArrayCopy() part. Is there some simple way of accessing the array (internally in ["storage":"ArrayObject":private])?
Thanks
Method chaining is using the return value of a function, in this case this is the reference to the object. Predicting the use of a returned value is generally not possible.
You have to tell the called method that you want to do something different. You can use the second argument for this, e.g. you return a different result if the second argument is defined. The other option might be to modify the class so that it behaves like an array except if it is printed.
I need to be able to call a function, but the function name is stored in a variable, is this possible? e.g:
function foo ()
{
//code here
}
function bar ()
{
//code here
}
$functionName = "foo";
// I need to call the function based on what is $functionName
$functionName() or call_user_func($functionName)
My favorite version is the inline version:
${"variableName"} = 12;
$className->{"propertyName"};
$className->{"methodName"}();
StaticClass::${"propertyName"};
StaticClass::{"methodName"}();
You can place variables or expressions inside the brackets too!
Solution: Use PHP7
Note: For a summarized version, see TL;DR at the end of the answer.
Old Methods
Update: One of the old methods explained here has been removed. Refer to other answers for explanation on other methods, it isn't covered here. By the way, if this answer doesn't help you, you should return upgrading your stuff. PHP 5.6 support has ended in January 2019 (now even PHP 7.2 and 7.3 are not being supported). See supported versions for more information.
As others mentioned, in PHP5 (and also in newer versions like PHP7) we could use variables as function names, use call_user_func() and call_user_func_array(), etc.
New Methods
As of PHP7, there are new ways introduced:
Note: Everything inside <something> brackets means one or more expressions to form something, e.g. <function_name> means expressions forming a function name.
Dynamic Function Call: Function Name On-the-fly
We can form a function name inside parentheses in just one go:
(<function_name>)(arguments);
For example:
function something(): string
{
return "something";
}
$bar = "some_thing";
(str_replace("_", "", $bar))(); // something
// Possible, too; but generally, not recommended, because makes your
// code more complicated
(str_replace("_", "", $bar))()();
Note: Although removing the parentheses around str_replace() is not an error, putting parentheses makes code more readable. However, you cannot do that sometimes, e.g. while using . operator. To be consistent, I recommend you to put the parentheses always.
Dynamic Function Call: Callable Property
A useful example would be in the context of objects: If you have stored a callable in a property, you have to call it this way:
($object->{<property_name>})();
As a simple example:
// Suppose we're in a class method context
($this->eventHandler)();
Obviously, calling it as $this->eventHandler() is plain wrong: By that you mean calling a method named eventHandler.
Dynamic Method Call: Method Name On-the-fly
Just like dynamic function calls, we can do the same way with method calls, surrounded by curly braces instead of parentheses (for extra forms, navigate to TL;DR section):
$object->{<method_name>}(arguments);
$object::{<method_name>}(arguments);
See it in an example:
class Foo
{
public function another(): string
{
return "something";
}
}
$bar = "another thing";
(new Something())->{explode(" ", $bar)[0]}(); // something
Dynamic Method Call: The Array Syntax
A more elegant way added in PHP7 is the following:
[<object>, <method_name>](arguments);
[<class_name>, <method_name>](arguments); // Static calls only
As an example:
class Foo
{
public function nonStaticCall()
{
echo "Non-static call";
}
public static function staticCall()
{
echo "Static call";
}
}
$x = new X();
[$x, "non" . "StaticCall"](); // Non-static call
[$x, "static" . "Call"](); // Static call
Note: The benefit of using this method over the previous one is that, you don't care about the call type (i.e. whether it's static or not).
Note: If you care about performance (and micro-optimizations), don't use this method. As I tested, this method is really slower than other methods (more than 10 times).
Extra Example: Using Anonymous Classes
Making things a bit complicated, you could use a combination of anonymous classes and the features above:
$bar = "SomeThing";
echo (new class {
public function something()
{
return 512;
}
})->{strtolower($bar)}(); // 512
TL;DR (Conclusion)
Generally, in PHP7, using the following forms are all possible:
// Everything inside `<something>` brackets means one or more expressions
// to form something
// Dynamic function call via function name
(<function_name>)(arguments);
// Dynamic function call on a callable property
($object->{<property_name>})(arguments);
// Dynamic method call on an object
$object->{<method_name>}(arguments);
$object::{<method_name>}(arguments);
// Dynamic method call on a dynamically-generated object
(<object>)->{<method_name>}(arguments);
(<object>)::{<method_name>}(arguments);
// Dynamic method call, statically
ClassName::{<method_name>}(arguments);
(<class_name>)::{<method_name>}(arguments);
// Dynamic method call, array-like (no different between static
// and non-static calls
[<object>, <method_name>](arguments);
// Dynamic method call, array-like, statically
[<class_name>, <method_name>](arguments);
Special thanks to this PHP talk.
Yes, it is possible:
function foo($msg) {
echo $msg."<br />";
}
$var1 = "foo";
$var1("testing 1,2,3");
Source: http://www.onlamp.com/pub/a/php/2001/05/17/php_foundations.html?page=2
As already mentioned, there are a few ways to achieve this with possibly the safest method being call_user_func() or if you must you can also go down the route of $function_name(). It is possible to pass arguments using both of these methods as so
$function_name = 'foobar';
$function_name(arg1, arg2);
call_user_func_array($function_name, array(arg1, arg2));
If the function you are calling belongs to an object you can still use either of these
$object->$function_name(arg1, arg2);
call_user_func_array(array($object, $function_name), array(arg1, arg2));
However if you are going to use the $function_name() method it may be a good idea to test for the existence of the function if the name is in any way dynamic
if(method_exists($object, $function_name))
{
$object->$function_name(arg1, arg2);
}
A few years late, but this is the best manner now imho:
$x = (new ReflectionFunction("foo"))->getClosure();
$x();
In case someone else is brought here by google because they were trying to use a variable for a method within a class, the below is a code sample which will actually work. None of the above worked for my situation. The key difference is the & in the declaration of $c = & new... and &$c being passed in call_user_func.
My specific case is when implementing someone's code having to do with colors and two member methods lighten() and darken() from the csscolor.php class. For whatever reason, I wanted to have the same code be able to call lighten or darken rather than select it out with logic. This may be the result of my stubbornness to not just use if-else or to change the code calling this method.
$lightdark="lighten"; // or optionally can be darken
$color="fcc"; // a hex color
$percent=0.15;
include_once("csscolor.php");
$c = & new CSS_Color($color);
$rtn=call_user_func( array(&$c,$lightdark),$color,$percent);
Note that trying anything with $c->{...} didn't work. Upon perusing the reader-contributed content at the bottom of php.net's page on call_user_func, I was able to piece together the above. Also, note that $params as an array didn't work for me:
// This doesn't work:
$params=Array($color,$percent);
$rtn=call_user_func( array(&$c,$lightdark),$params);
This above attempt would give a warning about the method expecting a 2nd argument (percent).
For the sake of completeness, you can also use eval():
$functionName = "foo()";
eval($functionName);
However, call_user_func() is the proper way.
Dynamic function names and namespaces
Just to add a point about dynamic function names when using namespaces.
If you're using namespaces, the following won't work except if your function is in the global namespace:
namespace greetings;
function hello()
{
// do something
}
$myvar = "hello";
$myvar(); // interpreted as "\hello();"
What to do?
You have to use call_user_func() instead:
// if hello() is in the current namespace
call_user_func(__NAMESPACE__.'\\'.$myvar);
// if hello() is in another namespace
call_user_func('mynamespace\\'.$myvar);
Complementing the answer of #Chris K if you want to call an object's method, you can call it using a single variable with the help of a closure:
function get_method($object, $method){
return function() use($object, $method){
$args = func_get_args();
return call_user_func_array(array($object, $method), $args);
};
}
class test{
function echo_this($text){
echo $text;
}
}
$test = new test();
$echo = get_method($test, 'echo_this');
$echo('Hello'); //Output is "Hello"
I posted another example here
Use the call_user_func function.
What I learnt from this question and the answers. Thanks all!
Let say I have these variables and functions:
$functionName1 = "sayHello";
$functionName2 = "sayHelloTo";
$functionName3 = "saySomethingTo";
$friend = "John";
$datas = array(
"something"=>"how are you?",
"to"=>"Sarah"
);
function sayHello()
{
echo "Hello!";
}
function sayHelloTo($to)
{
echo "Dear $to, hello!";
}
function saySomethingTo($something, $to)
{
echo "Dear $to, $something";
}
To call function without arguments
// Calling sayHello()
call_user_func($functionName1);
Hello!
To call function with 1 argument
// Calling sayHelloTo("John")
call_user_func($functionName2, $friend);
Dear John, hello!
To call function with 1 or more arguments
This will be useful if you are dynamically calling your functions and each function have different number of arguments. This is my case that I have been looking for (and solved). call_user_func_array is the key
// You can add your arguments
// 1. statically by hard-code,
$arguments[0] = "how are you?"; // my $something
$arguments[1] = "Sarah"; // my $to
// 2. OR dynamically using foreach
$arguments = NULL;
foreach($datas as $data)
{
$arguments[] = $data;
}
// Calling saySomethingTo("how are you?", "Sarah")
call_user_func_array($functionName3, $arguments);
Dear Sarah, how are you?
Yay bye!
If you were in a object context trying to call a function dynamically please try something like this code bellow:
$this->{$variable}();
The easiest way to call a function safely using the name stored in a variable is,
//I want to call method deploy that is stored in functionname
$functionname = 'deploy';
$retVal = {$functionname}('parameters');
I have used like below to create migration tables in Laravel dynamically,
foreach(App\Test::$columns as $name => $column){
$table->{$column[0]}($name);
}
Following code can help to write dynamic function in PHP.
now the function name can be dynamically change by variable '$current_page'.
$current_page = 'home_page';
$function = #${$current_page . '_page_versions'};
$function = function() {
echo 'current page';
};
$function();
Considering some of the excellent answers given here, sometimes you need to be precise.
For example.
if a function has a return value eg (boolean,array,string,int,float
e.t.c).
if the function has no return value check
if the function exists
Let's look at its credit to some of the answers given.
Class Cars{
function carMake(){
return 'Toyota';
}
function carMakeYear(){
return 2020;
}
function estimatedPriceInDollar{
return 1500.89;
}
function colorList(){
return array("Black","Gold","Silver","Blue");
}
function carUsage(){
return array("Private","Commercial","Government");
}
function getCar(){
echo "Toyota Venza 2020 model private estimated price is 1500 USD";
}
}
We want to check if method exists and call it dynamically.
$method = "color List";
$class = new Cars();
//If the function have return value;
$arrayColor = method_exists($class, str_replace(' ', "", $method)) ? call_user_func(array($this, $obj)) : [];
//If the function have no return value e.g echo,die,print e.t.c
$method = "get Car";
if(method_exists($class, str_replace(' ', "", $method))){
call_user_func(array($class, $method))
}
Thanks
One unconventional approach, that came to my mind is, unless you are generating the whole code through some super ultra autonomous AI which writes itself, there are high chances that the functions which you want to "dynamically" call, are already defined in your code base. So why not just check for the string and do the infamous ifelse dance to summon the ...you get my point.
eg.
if($functionName == 'foo'){
foo();
} else if($functionName == 'bar'){
bar();
}
Even switch-case can be used if you don't like the bland taste of ifelse ladder.
I understand that there are cases where the "dynamically calling the function" would be an absolute necessity (Like some recursive logic which modifies itself). But most of the everyday trivial use-cases can just be dodged.
It weeds out a lot of uncertainty from your application, while giving you a chance to execute a fallback function if the string doesn't match any of the available functions' definition. IMHO.
I dont know why u have to use that, doesnt sound so good to me at all, but if there are only a small amount of functions, you could use a if/elseif construct.
I dont know if a direct solution is possible.
something like
$foo = "bar";
$test = "foo";
echo $$test;
should return bar, you can try around but i dont think this will work for functions
I've got a PHPUnit mock object that returns 'return value' no matter what its arguments:
// From inside a test...
$mock = $this->getMock('myObject', 'methodToMock');
$mock->expects($this->any))
->method('methodToMock')
->will($this->returnValue('return value'));
What I want to be able to do is return a different value based on the arguments passed to the mock method. I've tried something like:
$mock = $this->getMock('myObject', 'methodToMock');
// methodToMock('one')
$mock->expects($this->any))
->method('methodToMock')
->with($this->equalTo('one'))
->will($this->returnValue('method called with argument "one"'));
// methodToMock('two')
$mock->expects($this->any))
->method('methodToMock')
->with($this->equalTo('two'))
->will($this->returnValue('method called with argument "two"'));
But this causes PHPUnit to complain if the mock isn't called with the argument 'two', so I assume that the definition of methodToMock('two') overwrites the definition of the first.
So my question is: Is there any way to get a PHPUnit mock object to return a different value based on its arguments? And if so, how?
Use a callback. e.g. (straight from PHPUnit documentation):
<?php
class StubTest extends PHPUnit_Framework_TestCase
{
public function testReturnCallbackStub()
{
$stub = $this->getMock(
'SomeClass', array('doSomething')
);
$stub->expects($this->any())
->method('doSomething')
->will($this->returnCallback('callback'));
// $stub->doSomething() returns callback(...)
}
}
function callback() {
$args = func_get_args();
// ...
}
?>
Do whatever processing you want in the callback() and return the result based on your $args as appropriate.
From the latest phpUnit docs: "Sometimes a stubbed method should return different values depending on a predefined list of arguments. You can use returnValueMap() to create a map that associates arguments with corresponding return values."
$mock->expects($this->any())
->method('getConfigValue')
->will(
$this->returnValueMap(
array(
array('firstparam', 'secondparam', 'retval'),
array('modes', 'foo', array('Array', 'of', 'modes'))
)
)
);
I had a similar problem (although slightly different... I didn't need different return value based on arguments, but had to test to ensure 2 sets of arguments were being passed to the same function). I stumbled upon using something like this:
$mock = $this->getMock();
$mock->expects($this->at(0))
->method('foo')
->with(...)
->will($this->returnValue(...));
$mock->expects($this->at(1))
->method('foo')
->with(...)
->will($this->returnValue(...));
It's not perfect, since it requires that the order of the 2 calls to foo() is known, but in practice this probably isn't too bad.
You would probably want to do a callback in a OOP fashion:
<?php
class StubTest extends PHPUnit_Framework_TestCase
{
public function testReturnAction()
{
$object = $this->getMock('class_name', array('method_to_mock'));
$object->expects($this->any())
->method('method_to_mock')
->will($this->returnCallback(array($this, 'returnTestDataCallback')));
$object->returnAction('param1');
// assert what param1 should return here
$object->returnAction('param2');
// assert what param2 should return here
}
public function returnTestDataCallback()
{
$args = func_get_args();
// process $args[0] here and return the data you want to mock
return 'The parameter was ' . $args[0];
}
}
?>
It is not exactly what you ask, but in some cases it can help:
$mock->expects( $this->any() ) )
->method( 'methodToMock' )
->will( $this->onConsecutiveCalls( 'one', 'two' ) );
onConsecutiveCalls - returns a list of values in the specified order
Pass two level array, where each element is an array of:
first are method parameters, and last is return value.
example:
->willReturnMap([
['firstArg', 'secondArg', 'returnValue']
])
You also can return the argument as follows:
$stub = $this->getMock(
'SomeClass', array('doSomething')
);
$stub->expects($this->any())
->method('doSomething')
->will($this->returnArgument(0));
As you can see in the Mocking documentation, the method returnValue($index) allows to return the given argument.
Do you mean something like this?
public function TestSomeCondition($condition){
$mockObj = $this->getMockObject();
$mockObj->setReturnValue('yourMethod',$condition);
}
I had a similar problem which I couldn't work out as well (there's surprisingly little information about for PHPUnit). In my case, I just made each test separate test - known input and known output. I realised that I didn't need to make a jack-of-all-trades mock object, I only needed a specific one for a specific test, and thus I separated the tests out and can test individual aspects of my code as a separate unit. I'm not sure if this might be applicable to you or not, but that's down to what you need to test.
$this->BusinessMock = $this->createMock('AppBundle\Entity\Business');
public function testBusiness()
{
/*
onConcecutiveCalls : Whether you want that the Stub returns differents values when it will be called .
*/
$this->BusinessMock ->method('getEmployees')
->will($this->onConsecutiveCalls(
$this->returnArgument(0),
$this->returnValue('employee')
)
);
// first call
$this->assertInstanceOf( //$this->returnArgument(0),
'argument',
$this->BusinessMock->getEmployees()
);
// second call
$this->assertEquals('employee',$this->BusinessMock->getEmployees())
//$this->returnValue('employee'),
}
Try :
->with($this->equalTo('one'),$this->equalTo('two))->will($this->returnValue('return value'));