如何使用数组将字符串替换为另一个字符串？

I am trying to work with an external array that should transform my file endings into another string:

This is my fileTypes.php:

return array(
'mp3'   => 'fa-music',
'jpeg'  => 'fa-picture-o',
);

And this is my index.php:

$fileTypes = require('fileTypes.php');
$file = "mymusic.mp3"
$fileExt = strtolower(pathinfo($file, PATHINFO_EXTENSION));

echo $fileTypes['fileExt'];

I do not really get it run. I must have some basic problem in understanding :( I get an empty result. But the result I wish is fa-music.

Your fileTypes.php file would be like this:

$fileTypes = array(
  'mp3'   => 'fa-music',
  'jpeg'  => 'fa-picture-o',
);

Now, just include that file in your main script:

require('fileTypes.php');
$file = "mymusic.mp3";
$fileExt = strtolower(pathinfo($file, PATHINFO_EXTENSION));

echo $fileTypes[$fileExt];