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# \$1isoDayOfWeek
<a name="isoDayOfWeek"></a>

Amazon DocumentDB 中的`$isoDayOfWeek`運算子會將日期的一週中的 ISO 日期傳回為整數值。ISO 週日期系統定義每週從星期一開始到星期日結束，第 1 週是包含當年第一個星期四的一週。

**參數**
+ `expression`：傳回一週中 ISO 日期的日期表達式。

## 範例 (MongoDB Shell)
<a name="isoDayOfWeek-examples"></a>

下列範例示範如何使用 `$isoDayOfWeek`運算子來擷取一組事件文件的 ISO 星期幾。

**建立範例文件**

```
db.events.insertMany([
  { _id: 1, eventDate: ISODate("2023-04-01T12:00:00Z") },
  { _id: 2, eventDate: ISODate("2023-04-02T12:00:00Z") },
  { _id: 3, eventDate: ISODate("2023-04-03T12:00:00Z") },
  { _id: 4, eventDate: ISODate("2023-04-04T12:00:00Z") },
  { _id: 5, eventDate: ISODate("2023-04-05T12:00:00Z") },
  { _id: 6, eventDate: ISODate("2023-04-06T12:00:00Z") },
  { _id: 7, eventDate: ISODate("2023-04-07T12:00:00Z") }
]);
```

**查詢範例**

```
db.events.aggregate([
  { $project: {
    _id: 1,
    eventDate: 1,
    isoDayOfWeek: { $isoDayOfWeek: "$eventDate" }
  }}
]);
```

**輸出**

```
[
  { "_id": 1, "eventDate": ISODate("2023-04-01T12:00:00Z"), "isoDayOfWeek": 6 },
  { "_id": 2, "eventDate": ISODate("2023-04-02T12:00:00Z"), "isoDayOfWeek": 7 },
  { "_id": 3, "eventDate": ISODate("2023-04-03T12:00:00Z"), "isoDayOfWeek": 1 },
  { "_id": 4, "eventDate": ISODate("2023-04-04T12:00:00Z"), "isoDayOfWeek": 2 },
  { "_id": 5, "eventDate": ISODate("2023-04-05T12:00:00Z"), "isoDayOfWeek": 3 },
  { "_id": 6, "eventDate": ISODate("2023-04-06T12:00:00Z"), "isoDayOfWeek": 4 },
  { "_id": 7, "eventDate": ISODate("2023-04-07T12:00:00Z"), "isoDayOfWeek": 5 }
]
```

## 程式碼範例
<a name="isoDayOfWeek-code"></a>

若要檢視使用 `$isoDayOfWeek`命令的程式碼範例，請選擇您要使用的語言標籤：

------
#### [ Node.js ]

```
const { MongoClient } = require('mongodb');

async function example() {
  const client = await MongoClient.connect('mongodb://<username>:<password>@<cluster-endpoint>:27017/?tls=true&tlsCAFile=global-bundle.pem&replicaSet=rs0&readPreference=secondaryPreferred&retryWrites=false');
  const db = client.db('test');
  const events = db.collection('events');

  const result = await events.aggregate([
    {
      $project: {
        _id: 1,
        eventDate: 1,
        isoDayOfWeek: { $isoDayOfWeek: '$eventDate' }
      }
    }
  ]).toArray();

  console.log(result);
  client.close();
}

example();
```

------
#### [ Python ]

```
from pymongo import MongoClient

def example():
    client = MongoClient('mongodb://<username>:<password>@<cluster-endpoint>:27017/?tls=true&tlsCAFile=global-bundle.pem&replicaSet=rs0&readPreference=secondaryPreferred&retryWrites=false')
    db = client.test
    events = db.events

    result = list(events.aggregate([
        {
            '$project': {
                '_id': 1,
                'eventDate': 1,
                'isoDayOfWeek': { '$isoDayOfWeek': '$eventDate' }
            }
        }
    ]))

    print(result)
    client.close()

example()
```

------