PHP Undefined Variable in a Closure

PHP Undefined variable in a closure

Inheriting variables from the parent scope

$row = array_map(function($n) use ($data) {
    $name = sprintf('point[%0d]', $n+1);
    $value = $data['measurements'][$n];
    return form_input($name, $value, "class='input-mini'");
}, range($i*6, $i*6+5));

Undefined variable inside a closure in PHP

You have to use the 'use' keyword to pass variables from the parent scope to the closure:

@for ($i=1; $i <= 12; $i++)
{!!           
    ($substance->consumptions->filter(function($consumption, $key) use ($i){
        return $consumption->date->month == $i;
    })->sum('quantity'))
!!},
@endfor

Hope this helps

why undefined variable in closure laravel?

u create a closure but did not pass parameter into Closure so your code is not working

since inside the closure PHP doesn't know the $my_profile_id variable you need to have a use statement in the closure too

$my_user_id = Auth::user()->id;
$my_profile_id =   DB::table('profiles')->select('profiles.profile_id', 'profiles.id')->leftjoin('users','users.id' ,'=' ,'profiles.id')->where('users.id',$my_user_id)->pluck('profiles.profile_id')->first();

$friend_accept = DB::table('friend_request')->select('profiles.profile_id','profiles.first_name','interest_request.sent_at','interest_request.interest_id')->leftjoin('profiles', function($join){
$join->on('interest_request.sender_id' , '=','profiles.profile_id');
$join->orOn('interest_request.to_user_id' , '=','profiles.profile_id');
 })->where('to_user_id',$my_profile_id)
   ->orwhere('sender_id',$my_profile_id)
   ->where('interest_status','2')
   ->whereNotIn('profiles.profile_id', function($q) use ($my_profile_id) {
           $q->select('profiles.profile_id')->from('profiles')
                ->where('profiles.profile_id',$my_profile_id);
   })->groupby('profiles.profile_id')->get(); 

for more info about Closure see

Lumen 5.3 Undefined variable: closure

The closure should be the last item in your array. Change your route to:

$app->get('/', ['middleware'=>'auth', function () use ($app) {
    return $app->version();
}]);

Laravel Cache, variable inside closure undefined?

You should allow anonymous function to capture the variable outside the scope. $entity_id its outside the scope. This is how php express the closure. With a use() would work.

public function entity($entity_id, Request $request)
{
$expiresAt = Carbon::now()->addMinutes(10);
$entity = Cache::remember('entities', $expiresAt, function () use($entity_id) {
    return Entity::where('id', $entity_id)
        ->with('address')
        ->with('_geoloc')
        ->first();
});

Why is a variable used by reference to the set_error_handler function closure undefined?

The &$error is making the code work. Basically, it's assigning the $error variable to null when you pass the callable, and then inside, it's setting it to the error message, and used afterwards.

set_error_handler(function ($type, $msg) use (&$error) { $error = $msg; });
$moved = move_uploaded_file($this->getPathname(), $target);
restore_error_handler();

Then it is using the $error variable if it failed to move:

if (!$moved) {
    throw new FileException(sprintf('Could not move the file "%s" to "%s" (%s)', $this->getPathname(), $target, strip_tags($error)));
}

It's the same as:

$error = null;
set_error_handler(function ($type, $msg) use (&$error) { $error = $msg; });

Without the &, it will throw an undefined variable notice.

And no the $error variable is not related to the error property.

You can take this code for example:

function executeCallback($callable) {
    $callable();   
}

executeCallback(function () use (&$error) {
    $error = 'This is the error message.';
});

echo $error;

The $error variable is defined in the use (&$error) and used afterward. And the output of the echo would be:

This is the error message.

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