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

Amazon DocumentDB 中的`$isoWeekYear`运算符返回给定日期的 ISO 8601 周年号。ISO 周年号与公历年的不同之处在于，周年可能与日历年不同，尤其是在年初和年底。

**参数**
+ `expression`：要返回 ISO 8601 周年号的日期表达式。

## 示例（MongoDB 外壳）
<a name="isoWeekYear-examples"></a>

此示例演示如何使用`$isoWeekYear`运算符检索事件集合中每个文档的日期字段的 ISO 8601 周年。

**创建示例文档**

```
db.events.insertMany([
  { _id: 1, name: "Event 1", date: ISODate("2022-12-31T00:00:00Z") },
  { _id: 2, name: "Event 2", date: ISODate("2023-01-01T00:00:00Z") },
  { _id: 3, name: "Event 3", date: ISODate("2023-01-02T00:00:00Z") }
]);
```

**查询示例**

```
db.events.aggregate([
  { $project: {
    name: 1,
    isoWeekYear: { $isoWeekYear: "$date" }
  }}
]);
```

**输出**

```
[
  { "_id" : 1, "name" : "Event 1", "isoWeekYear" : 2023 },
  { "_id" : 2, "name" : "Event 2", "isoWeekYear" : 2023 },
  { "_id" : 3, "name" : "Event 3", "isoWeekYear" : 2023 }
]
```

## 代码示例
<a name="isoWeekYear-code"></a>

要查看使用该`$isoWeekYear`命令的代码示例，请选择要使用的语言的选项卡：

------
#### [ 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: {
      name: 1,
      isoWeekYear: { $isoWeekYear: '$date' }
    }}
  ]).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([
        { '$project': {
            'name': 1,
            'isoWeekYear': { '$isoWeekYear': '$date' }
        }}
    ]))

    print(result)
    client.close()

example()
```

------