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up vote 6 down vote favorite
2

I need to use variable function names for a project I'm working on but have run into a bit of strange issue. The function name ends up as a string element in an array.

This works:

$func = $request[2];
$pages->$func();

This doesn't:

$pages->$request[2]();

And I can't figure out why. It throws an array to string conversion error, as if it's ignoring that I have supplied a key to a specific element. Is this just how it works or am I doing something wrong?

share|improve this question
up vote 5 down vote accepted

As for php 5, you can use curly-braced syntax:

$pages->{$request[2]}();

Simple enough examlpe to reproduce:

<?php

$request = [
    2 => 'test'
];

class Pages
{
    function test()
    {
        return 1;
    }
}

$pages = new Pages();

echo $pages->{$request[2]}();

Alternatively (as you noted in the question):

$methodName = $request[2];
$pages->$methodName();

Quote from php.net for php 7 case:

Indirect access to variables, properties, and methods will now be evaluated strictly in left-to-right order, as opposed to the previous mix of special cases.

Also there is a table for php 5 and php 7 differences for this matter just below quote in the docs I've supplied here.

Which things you should consider:

  • Check value of the $request[2] (is it really a string?).
  • Check your version of php (is it php 5+ or php 7+?).
  • Check manual on variable functions for your release.
share|improve this answer
    
Thank you! I was looking for documentation covering this and couldn't find it. I'll accept your answer as soon as the timer lets me. – user1377362 Oct 14 at 3:20
1  
Beat me too it, +1 Could also ( maybe ? ) use ReflectionFunction class and invoke, but it's a bit overkill for this. php.net/manual/en/class.reflectionfunction.php – ArtisticPhoenix Oct 14 at 3:27
    
@ArtisticPhoenix yeah, there is also call_user_func(). Still, I believe, that this question is about syntax more, than about solution to a problem. – Num6 Oct 14 at 3:36

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