PHP Use different custom functions inside another custom function

Question

I have created function

function do_stuff($text) {
   $new_text = nl2br($text);

   return $new_text;
}

$result = do_stuff("Hello \n World!"); 
//returns "Hello <br /> World!"

I want to be able to supply another simple built in PHP function e.g. strtoupper() inside my function somehow, its not just strtoupper() that i need, i need ability to supply different functions into my do_stuff() function.

Say i want to do something like this.

$result = do_stuff("Hello \n World!", "strtolower()");
//returns "Hello <br /> World!"

How would i make this work without creating another function.

function do_stuff($text, $sub_function='') {
   $new_text = nl2br($text);

   $sub_function($new_text);

   return $new_text;
}

$result = do_stuff("Hello \n World!"); 
//returns "Hello <br /> World!"

P.S. Just remembered variable variables, and googled, there's actually is Variable functions too, might answer this one myself.

http://php.net/manual/en/functions.variable-functions.php

I don't understand. What you're asking you have achieved in your second example. — AbraCadaver
– AbraCadaver, Commented Dec 4, 2014 at 16:23
Will second example work? i just randomly made it up. Edit wow it does work i just forgot to assign sub function value to $new_text variable :) — Roman Toasov
– Roman Toasov, Commented Dec 4, 2014 at 16:25

AbraCadaver · Accepted Answer · 2014-12-04 16:27:28Z

1

You have it in your second example. Just make sure to check that it exists and then assign the return to the string. There is an assumption here about what the function accepts/requires as args and what it returns:

function do_stuff($text, $function='') {
    $new_text = nl2br($text);

    if(function_exists($function)) {
        $new_text = $function($new_text);
    }
    return $new_text;
}

$result = do_stuff("Hello \n World!", "strtoupper");

answered Dec 4, 2014 at 16:27

AbraCadaver

79.2k7 gold badges75 silver badges91 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Roman Toasov Over a year ago

Thanks you were first. How to pass multiple arguments to function say if $function="str_ireplace"; ?

Roman Toasov Over a year ago

Ended up using call_user_func_array("function", $args_arr) as it supports multiple arguments in any order e.g. i can do both str_ireplace("find", "", $text) and stristr($text, "find") with them having arguments in different order

Rangad · Accepted Answer · 2014-12-04 16:42:36Z

Callables can be strings, arrays with a specific format, instances of the Closure class created using the function () {};-syntax and classes implementing __invoke directly. You can pass any of these to your function and call them using $myFunction($params) or call_user_func($myFunction, $params).

Additionally to the string examples already given in other answers you may also define a (new) function (closure). This might be especially beneficial if you only need the contained logic in one place and a core function is not suitable. You can also wrap paramters and pass additional values from the defining context that way:

Please be aware that the callable typehint requires php 5.4+

function yourFunction($text, callable $myFunction) { return $myFunction($text); }

$offset = 5;

echo yourFunction('Hello World', function($text) use($offset) {
    return substr($text, $offset);
});

Output: http://3v4l.org/CFMrI

Documentation hints to read on:

Bart Friederichs · Accepted Answer · 2014-12-04 16:27:07Z

0

You can call a function like this:

$fcn = "strtoupper";
$fcn();

in the same way (as you found out yourself), you can have variable variables:

$a = "b";
$b = 4;
$$a;    // 4

answered Dec 4, 2014 at 16:27

Bart Friederichs

33.8k16 gold badges112 silver badges219 bronze badges

Comments

mopo922 · Accepted Answer · 2014-12-04 16:31:16Z

0

Looks like you're almost there, just need to leave off the parentheses in the second parameter:

$result = do_stuff("Hello \n World!", "strtolower");

Then this should work after a little cleanup:

function do_stuff($text, $sub_function='') {
   $new_text = nl2br($text);

   if ($sub_function) {
      $new_text = $sub_function($new_text);
   }

   return $new_text;
}

answered Dec 4, 2014 at 16:31

mopo922

6,3813 gold badges30 silver badges31 bronze badges

Collectives™ on Stack Overflow

PHP Use different custom functions inside another custom function

4 Answers 4

2 Comments

Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

2 Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related