PHP Array Search - key => string

Question

I got some trouble with in_array()

$list = array(
    "files/" => "/system/application/files/_index.php",
    "misc/chat/" => "/system/application/misc/chat/_index.php"
);

I have this $_GET['f'] which holds the string files/.
How can I search through the array for possible matches?

If the string is found in the array, then the file should be included

Thanks for any help :)

Answer 1

It's really simple. All you need to do is check if the array element is set. The language construct that's usually used is isset() (yes, it's that obvious)...

if (isset($list[$_GET['f']])) {
}

There's no need to call a function for this, isset is cleaner and easier to read (IMHO)...

Note that isset is not actually a function. It's a language construct. That has a few implications:

1. You can't use isset on the return from a function (isset(foo()) won't work). It will only work on a variable (or a composition of variables such as array accessing or object accessing).

2. It doesn't have the overhead of a function call, so it's always fast. The overall overhead of a function call is a micro-optimization to worry about, but it's worth mentioning if you're in a tight loop, it can add up.

3. You can't call isset as a variable function. This won't work:

   $func = 'isset';
   $func($var);