二维数组根据某个字段去重并统计个数

    public function census() {
        
        $data = $this->request->post("params/a");
        
        // $data = [
        //     ['name' => 'Alice', 'specId' => 25],
        //     ['name' => 'Bob', 'specId' => 25],
        //     ['name' => 'Charlie', 'specId' => 26],
        //     ['name' => 'Alice', 'specId' => 26],
        //     ['name' => 'Bob', 'specId' => 26],
        // ];

        // 按字段分组
        $grouped = array_reduce($data, function ($carry, $item) {
            $carry[$item['specId']][] = $item;
            return $carry;
        }, []);
         
        // 计算每个分组的数量
        $groupCounts = array_map(function ($group) {
            return count($group);
        }, $grouped);

        // print_r($groupCounts);
                
        // 使用array_column()获取特定字段，然后用array_unique()获取唯一值
        $uniqueItems = array_values(array_unique(array_column($data, 'specId'), SORT_REGULAR));
         
        // 使用array_filter()重新组装数组
        $filteredArray = array_filter($data, function ($item) use ($uniqueItems) {
            static $found = [];
            if (in_array($item['specId'], $found)) {
                return false; // 如果已经找到，不包含在结果中
            } else {
                $found[] = $item['specId']; // 标记为找到
                return true;
            }
        });
         
        // print_r($filteredArray);exit();

        foreach($filteredArray as $key => $val) {
            if(isset($groupCounts[$val['specId']])) {
                $filteredArray[$key]['num'] = $groupCounts[$val['specId']];
            }
        }

        $this->success('',$filteredArray);
        
    }