Is PHP variable value case sensitive

A website I develop currently have a section that allows users to name things, but I don't want they give any names to anything. So I restrict words which they could use. My current code look like this:

$given_name = trim($_POST['given_name']);

$reserve = array(
        .......
        "demo" => "demo",
        "Demo" => "Demo",
        "example" => "example",
        "Example" => "Example",
        .......
);

if (in_array($given_name,$reserve)) {
        die(msg(0,"[ ".$given_name." ] is unavailable."));
}

Code (markup):

The list is long and I don't think I will be able to list everything I don't want the users to use.

Can I just do it like this, is it valid:

$reserve = array(
        .......
        "demo" => "demo",
        "example" => "example",
        .......
);

Code (markup):

Thank you,

 

keys should be case sensitive... though I'm not quite sure what the blazes you are setting associative keys for since you're using in_array.

Which in_array is case sensitive. Honestly this seems more like a job for a regular expression or stripos. The latter would be ideal as then it's just check for a non boolean false.

$reservedWords = [
	"demo",
	"example"
];

foreach ($reservedWords as $word) {
	if (stripos($given_name, $word) !== false) die('your message here');
}

Code (markup):

 

Thanks for quick response.
It comes in time needed.

And thanks for suggestion. I'll further study about it.