How to fix laravel collection chunk loop once?

Question

I have a problem with laravel collection with chunk result. It run only one time in loop.

I have 204 elements in array and I want to split it as 100 each by using laravel collection helper. It must run in three times but I got only once.

    private function __migrateDistricts()
    {
        DB::beginTransaction();
        try {
            $file = 'resources/csv/districts.csv';
            $csv = array_map('str_getcsv', file($file));
            $table = 'districts';
            $collection = collect($csv);
            $arr_districts = array();
            foreach ($collection->chunk(100) as $districts) {
                foreach ($districts as $dist) {
                    array_push($arr_districts, $this->__transformDistricts($dist));
                }
                DB::table($table)->insert($arr_districts);
                DB::commit();
            }
        } catch (\Exception $e) {
            DB::rollBack();
        }
    }

    private function __transformDistricts($district)
    {
        $code = substr($district[3],0,2);
        $pro = DB::table('provinces')->where('code', $code)->first();
        return [ 
            'province_id' => $pro->id,
            'name_kh' => $district[1],
            'name_en' => $district[2],
            'code' => $district[3],
        ];
    }

After I run the I got only 100 records in table. It should be 204 records in table. What is wrong with my code? Thanks

What is the result if you add dd($collection->count()) right before the first foreach? — Mauro Baptista, Oct 13 '19 at 15:53

score 2 · Answer 1 · answered Oct 13 '19 at 16:40

In your code...

$arr_districts = array();
foreach ($collection->chunk(100) as $districts) {
    foreach ($districts as $dist) {
        array_push($arr_districts, $this->__transformDistricts($dist));
    }
    DB::table($table)->insert($arr_districts);
    DB::commit();
}

in each inner loop, you add the data to $arr_districts, which on the second time of your outer loop, will still contain the data from the first loop.

You should reset this array for each main loop to clear the data out...

foreach ($collection->chunk(100) as $districts) {
    $arr_districts = array();        // Move to here
    foreach ($districts as $dist) {
        array_push($arr_districts, $this->__transformDistricts($dist));
    }
    DB::table($table)->insert($arr_districts);
    DB::commit();
}

How to fix laravel collection chunk loop once?

1 Answers1