Get string based on another string

[NotionCommotion]

Given a text value $path, I want to return the actual path.  One option is a switch statement as shown below.  Another option is put them in an associated array (or maybe a static array?) and check if the element is set and if not throw an deception.  Or maybe a totally different solution.  Is one solution better (i.e. more efficient) than another?  I will probably be retrieving a path around 5 times for every server hit. Thanks

    function getPath($path)
    {
      switch($path){
        case 'classes': $path=__DIR__;break;
        case 'application': $path=dirname(__DIR__);break;
        case 'root': $path=dirname(dirname(__DIR__));break;
        case 'twig': $path=dirname(dirname(__DIR__)).'/vendor/autoload.php';break;
        case 'lib': $path=dirname(__DIR__).'/lib';break;
        case 'help': $path=dirname(__DIR__).'/lib/help';
        case 'templates': $path=dirname(__DIR__).'/lib/templates';
        case 'htdocs_base': $path=dirname(dirname(__DIR__)).'/html';
        case 'resources_base': $path=dirname(dirname(__DIR__)).'/user_resources';
        // About 10 more
        default: throw new Exception("Path {$path} not valid.");
      }
      return $path;
    }

 

[kicken]

Use whichever method you find most readable. The performance difference between the two is probably negligible (you could test it if your concerned/curious).

[NotionCommotion]

Thanks kicken,

 

Testing it as we speak.  The array method goes around twice as fast (but it is still like instant).

 

I am also curious on how much memory they both use.  I know it probably doesn't matter, but as I said, just curious.

 

I've never checked real time memory usage, and if you have a pointer, it would be appreciated.  If not, I am sure I will find something.

 

EDIT.  Took 2 seconds to google: http://php.net/manual/en/function.memory-get-usage.php

 

Thanks

Edited December 29, 2014 by NotionCommotion

[Jacques1]

An array has the least syntax noise and reflects the idea of mapping keys to paths, so I'd use that.

 

// Don't bother about micro-optimizations (or rather nano-optimizations in this case). I can assure you that there are much, much worse bottlenecks lurking somewhere in your application.

Edited December 29, 2014 by Jacques1

[NotionCommotion]

I'm not worried about micro-optimizations, just curious.  Do you know how to interpret memory usage?

 

Using a switch statement:

Time: 0.0052700042724609
memory_get_peak_usage(): 136328
memory_get_peak_usage(true): 262144
memory_get_usage(): 134860
memory_get_usage(true): 262144

Using an array:

Time: 0.0024628639221191
memory_get_peak_usage(): 137304
memory_get_peak_usage(true): 262144
memory_get_usage(): 136200
memory_get_usage(true): 262144

[kicken]

The array lookup method would be best if you can define it just once, but reference it multiple times. Either define it in a class constructor, or if this function is standalone you could use a static variable and initialize it on the first function call.

 

function getPath($path){
   static $map;
   if (!$map){
      //define array
   }

   if (isset($map[$path])) return $map[$path];
   throw new Exception("Path {$path} not valid.");
}

Edited December 29, 2014 by kicken