Undefined variable but it's already declared Laravel - laravel

Question

I'm having some problems with my website.
Lately, I've been working on a "filtering page" where the user selects/writes a character, and then it searches X data with that character (From A-Z and 0-9). The character can be optional.
This is my getAffiliates function:
public static function getAffiliates($community_id, $character) {
if (!empty($character)) {
$character = strval($character);
if (is_numeric($character)) {
$users = UserCommunity::with('user')->where('community_id', $community_id)->whereHas('user', function($q) {
$q->where('name', 'regexp', '^[0-9]+');
})->get();
} else {
$users = UserCommunity::with('user')->where('community_id', $community_id)->whereHas('user', function($q) {
$q->where('name', 'like', $character.'%');
})->get();
}
} else {
$users = UserCommunity::with('user')->where('community_id', $community_id)->take(50)->get();
}
return $users;
}
What this code does is, given an X $community_id, and an X $character, it will determine whether $character is integer or not. Then, it will do a query to the database and it will retrieve a collection conditioned on the given parameters. Basically, the query looks for a value where the initial character equals my $character parameter.
What I don't know is, why am I getting the "undefined variable $character" error?
My controller's code is this (Notice the parameter can be null):
Can someone explain what is actually wrong?
UPDATE With the Full Trace Error

Answer 1

You have to use variable top of where has function. to access it.
public static function getAffiliates($community_id, $character) {
if (!empty($character)) {
$character = strval($character);
if (is_numeric($character)) {
$users = UserCommunity::with('user')->where('community_id', $community_id)->whereHas('user', function($q) {
$q->where('name', 'regexp', '^[0-9]+');
})->get();
} else {
$users = UserCommunity::with('user')->where('community_id', $community_id)->whereHas('user', function($q) use ($character) {
$q->where('name', 'like', $character.'%');
})->get();
}
} else {
$users = UserCommunity::with('user')->where('community_id', $community_id)->take(50)->get();
}
return $users;
}

Answer 2

Your $character variable is defined outside the scope of where it's being used.
You can use the use keyword to bring the variable into the closure's scope like this:
$users = UserCommunity::with('user')->where('community_id', $community_id)
->whereHas('user', function($q) use($character) { // <-- do this
$q->where('name', 'like', $character.'%');
})->get();