Laravel集合分组数据处理：移除外层数组并修正结果

我需要先对获取的数据进行计算处理，再按id分组，但当前输出带有双层数组结构，希望移除外层数组，得到符合预期的结果。

当前输出数据 #

"data": [
        [
            {
                "id": 2,
                "runtime_batch": 24528,
                "smallstoptime_batch": 250,
                "downtime_batch": 200
            },
            {
                "id": 2,
                "runtime_batch": 2074,
                "smallstoptime_batch": 0,
                "downtime_batch": 1
            }
        ],
        [
            {
                "id": 3,
                "runtime_batch": 185,
                "smallstoptime_batch": 252,
                "downtime_batch": 1409
            },
            {
                "id": 3,
                "runtime_batch": 2127,
                "smallstoptime_batch": 377,
                "downtime_batch": 22452
            }
        ]
    ]

当前使用的代码 #

$linedata = GetMyData::select('id', 'runtime_batch', 'smallstoptime_batch', 'downtime_batch', 'output', 'output_final')->get();

foreach($linedata as $ld) {
    $ld->runtime_batch = round(($ld->runtime_batch+$ld->smallstoptime_batch)/($ld->runtime_batch+$ld->smallstoptime_batch+$ld->downtime_batch)*100, 2);
    $ld->downtime_batch = round($ld->output/$ld->output_final*100, 2);
    $ld->smallstoptime_batch = round($ld->output_final/($ld->runtime_batch+$ld->smallstoptime_batch)*100, 2);
}

$groupingline = collect($linedata)->groupBy('id')->values()->all();

解决方案 #

1. 先修正数据计算的潜在问题 #

原代码中计算smallstoptime_batch时，使用了已经被修改过的runtime_batch值，会导致计算结果偏差。建议改用getOriginal()获取数据库原始值计算，同时用集合的map方法替代foreach，更符合Laravel写法：

$linedata = GetMyData::select('id', 'runtime_batch', 'smallstoptime_batch', 'downtime_batch', 'output', 'output_final')
    ->get()
    ->map(function ($ld) {
        // 计算总时长（用原始值）
        $totalTime = $ld->getOriginal('runtime_batch') + $ld->getOriginal('smallstoptime_batch') + $ld->getOriginal('downtime_batch');
        // 计算runtime_batch
        $ld->runtime_batch = round(($ld->getOriginal('runtime_batch') + $ld->getOriginal('smallstoptime_batch')) / $totalTime * 100, 2);
        // 计算downtime_batch
        $ld->downtime_batch = round($ld->output / $ld->output_final * 100, 2);
        // 计算smallstoptime_batch（用原始值）
        $ld->smallstoptime_batch = round($ld->output_final / ($ld->getOriginal('runtime_batch') + $ld->getOriginal('smallstoptime_batch')) * 100, 2);
        return $ld;
    });

2. 移除双层数组结构的两种方式 #

方式一：将分组元素平铺为一维数组

如果需要把所有分组内的元素合并到一个单层数组中，使用flatten()方法：

$groupingline = $linedata->groupBy('id')->flatten()->all();

输出结果为：

"data": [
    {
        "id": 2,
        "runtime_batch": 24528,
        "smallstoptime_batch": 250,
        "downtime_batch": 200
    },
    {
        "id": 2,
        "runtime_batch": 2074,
        "smallstoptime_batch": 0,
        "downtime_batch": 1
    },
    {
        "id": 3,
        "runtime_batch": 185,
        "smallstoptime_batch": 252,
        "downtime_batch": 1409
    },
    {
        "id": 3,
        "runtime_batch": 2127,
        "smallstoptime_batch": 377,
        "downtime_batch": 22452
    }
]

方式二：保留分组结构但用id作为键

如果需要保留按id分组的逻辑，但不想用数字索引的外层数组，去掉values()方法即可，得到以id为键的关联数组：

$groupingline = $linedata->groupBy('id')->all();

输出结果为：

"data": {
    "2": [
        {
            "id": 2,
            "runtime_batch": 24528,
            "smallstoptime_batch": 250,
            "downtime_batch": 200
        },
        {
            "id": 2,
            "runtime_batch": 2074,
            "smallstoptime_batch": 0,
            "downtime_batch": 1
        }
    ],
    "3": [
        {
            "id": 3,
            "runtime_batch": 185,
            "smallstoptime_batch": 252,
            "downtime_batch": 1409
        },
        {
            "id": 3,
            "runtime_batch": 2127,
            "smallstoptime_batch": 377,
            "downtime_batch": 22452
        }
    ]
}

内容的提问来源于stack exchange，提问作者Test Doang