Javascript 如果ng.for小于表头（th），如何在表数据（td）中显示空消息？

我有这个代码在表中显示数据。迭代时我只有3辆车和3辆自行车，如何在表头（th）#4和#5中显示表数据（td）的空消息

我想找到一个动态的解决方案。因此，如果我的汽车或自行车少了，仍然显示空消息，或者如果我拥有所有的汽车或自行车，则不显示空消息

<table class="table table-bordered table-ranking text-center">
    <thead class="thead-light">
        <tr>
            <th class="no-bg"></th>
            <th>#1</th>
            <th>#2</th>
            <th>#3</th>
            <th>#4</th>
            <th>#5</th>
        </tr>
    </thead>
    <tbody class="thead-light">
        <tr>
            <th>Car</th>
            <td *ngFor="let car of ranking?.totals?.car">
                {{ car?.property?.name }}<br /><span
                    class="muted small">{{ car?.total / millionDivisor | number: '1.0-2' }} MM EUR
                    | {{ car?.percentage | number: '1.0-2' }}%</span>
            </td>
        </tr>
        <tr>
            <th>Bike</th>
            <td *ngFor="let bike of ranking?.totals?.bike">
                {{ bike?.property?.name }}<br /><span
                    class="muted small">{{ bike?.total / millionDivisor | number: '1.0-2' }} MM EUR
                    | {{ bike?.percentage | number: '1.0-2' }}%</span>
            </td>
        </tr>
    </tbody>
</table>

---

您可以使用索引和检查值是否未定义

{{排名？.totals？.car[index]？.property？.name}}
{{排名？.totals？.car[index]？.total/millionDivisor |编号：'1.0-2'}}毫米欧元
|{{排名？.总数？.汽车[指数]？.百分比|数字：'1.0-2'}}
没有可用的数据

---

演示：

你能提供一个用于排名的样本数据集吗？@Arctezy我在帖子中添加了数据样本。非常感谢@Arctezy。这个解决方案有效！

 ranking:{
 "totals": {
            "car": [
                {
                    "property": {
                        "_id": "5f8ffa5e4106274",
                        "name": "porsche",
                        "hash": "aCTGdtRUhy",
                        "createdAt": "2020-10-21T09:07:42.524Z",
                        "updatedAt": "2021-02-01T09:59:01.571Z",
                        "__v": 0
                    },
                    "total": 89687422,
                    "percentage": 99.99993756096029,
                    "ranking": 1
                },
                {
                    "property": {
                        "_id": "5fe413938125ad06272",
                        "name": "seat",
                        "hash": "UOMTGBb5L",
                        "createdAt": "2020-10-21T09:07:42.425Z",
                        "updatedAt": "2021-02-01T09:59:01.529Z",
                        "__v": 0
                    },
                    "total": 56,
                    "percentage": 0.00006243903970630104,
                    "ranking": 2
                },
                {
                    "property": {
                        "_id": "6069e612f1686a672c201",
                        "name": "mercedes",
                        "hash": "aCTGhh",
                        "createdAt": "2020-10-21T09:07:42.524Z",
                        "updatedAt": "2021-02-01T09:59:01.571Z",
                        "__v": 0
                    },
                    "total": 0,
                    "percentage": 0,
                    "ranking": 3
                }
            ],
            "bike": [
                {
                    "property": {
                        "_id": "5f8ffa5e413938125ad",
                        "name": "A",
                        "hash": "UGBb5L",
                        "createdAt": "2020-10-21T09:07:42.425Z",
                        "updatedAt": "2021-02-01T09:59:01.529Z",
                        "__v": 0
                    },
                    "total": 1286553.2196000002,
                    "percentage": 50.14333136951876,
                    "ranking": 1
                },
                {
                    "property": {
                        "_id": "538125ad06274",
                        "name": "B",
                        "hash": "GdtRUhy",
                        "createdAt": "2020-10-21T09:07:42.524Z",
                        "updatedAt": "2021-02-01T09:59:01.571Z",
                        "__v": 0
                    },
                    "total": 1279198.1664,
                    "percentage": 49.856668630481266,
                    "ranking": 2
                },
                {
                    "property": {
                        "_id": "12f1686a672c201",
                        "name": "C",
                        "hash": "aCRUhh",
                        "createdAt": "2020-10-21T09:07:42.524Z",
                        "updatedAt": "2021-02-01T09:59:01.571Z",
                        "__v": 0
                    },
                    "total": 0,
                    "percentage": 0,
                    "ranking": 3
                }
            ]
        }
}
```