PHP oop how can i call dynamic function name

Question

I have a method display() in the book class.

$name = 'display()';
$book = new Book('PHP Object-Oriented Solutions', 300);

$book->$name;

How can i call display method using $book->$name

I'm voting to close this question as off-topic because it is a duplicate of the PHP Manual. php.net/manual/en/functions.variable-functions.php — Hanky Panky
– Hanky Panky, Commented Dec 6, 2016 at 10:29
when I use $book->$name it says Notice: Undefined property: Book::$display() — Brijesh Mishra
– Brijesh Mishra, Commented Dec 6, 2016 at 10:32
Removing () from $name gives Undefined property: Book::$display — Brijesh Mishra
– Brijesh Mishra, Commented Dec 6, 2016 at 10:34

Narf · Accepted Answer · 2016-12-06 16:46:15Z

3

You need to tell PHP that you're trying to execute a method, not in the variable itself, but within the actual code:

$name = 'display';
$book = new Book('PHP Object-Oriented Solutions', 300);

$book->$name();

Otherwise, as you have seen, it will treat $name as a property name, and rightly so ... If you have both a property and a method named 'display', there wouldn't be a way to distinguish between the two using what you've tried.

answered Dec 6, 2016 at 16:46

Narf

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3 Comments

DaGhostman Dimitrov Over a year ago

Isn't that going to run the $name() first?

Narf Over a year ago

No, the lexer sees the OOP context and would ignore a regular function named display().

DaGhostman Dimitrov Over a year ago

wasn't sure about it and kind of couldn't test it :)

Narf · Accepted Answer · 2016-12-10 16:31:12Z

0

The cleanest way (imo at least) is to use something like:

$name = 'display';
$book = new Book('PHP Object-Oriented Solutions', 300);

call_user_func([$book, $name]); // This looks cleaner and/or more obvious on first sight.
// call_user_func_array([$book, $name], $arrayOfArguments);

// And as @Narf suggested (and I agree cuz we move forward)
call_user_func([$book, $name], ... $arrayOfArguments);

And yes you can pass parameters to this function, that will be passed to the function, but you have to list them after the callable array. in order to avoid doing that (hard to maintain and not always what you want) you can use call_user_func_array which accepts an array of arguments as second argument that is passed to the callable.

call_user_func Documentation

call_user_func_array Documentation

edited Dec 10, 2016 at 16:31

Narf

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answered Dec 6, 2016 at 16:51

DaGhostman Dimitrov

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3 Comments

Narf Over a year ago

Argument unpacking FTW: call_user_func([$book, $name], ... $argsArray);

DaGhostman Dimitrov Over a year ago

~Lol, that is if we are throwing 5.6 out the window (not mentioning others since EOL), but will edit~ Apparently I am dumb enough to forget they are 5.6 feature ... facepalm

Narf Over a year ago

That's a PHP 5.6 feature. ;) The EOLd versions can RIP.

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