php - undefined variable 'count'

Question

我已经有一段时间没有使用 PHP 了，所以我有点困惑为什么我在标题中收到错误

$count =0;
User::chunk(200, function ($users) {
    $count++;
    error_log('------------ chunck: '.$count);
});

Answer 1

您必须使用use，如文档(http://php.net/manual/en/functions.anonymous.php)中所述:

Closures may also inherit variables from the parent scope. Any such variables must be declared in the function header. Inheriting variables from the parent scope is not the same as using global variables. Global variables exist in the global scope, which is the same no matter what function is executing.

代码:

$count =0;
User::chunk(200, function ($users) use($count) {
    $count++;
    error_log('------------ chunck: '.$count);
});