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# $度 ToRadians
<a name="degreesToRadians"></a>

8.0.1 版中的新增内容。

Amazon DocumentDB 中的`$degreesToRadians`运算符将值从度转换为弧度。

**参数**
+ `expression`：解析为以度为单位的数值的表达式。

## 示例（MongoDB Shell）
<a name="degreesToRadians-examples"></a>

以下示例显示如何使用`$degreesToRadians`运算符将度数值转换为弧度。

**创建示例文档 **

```
db.angles.insertMany([
  { "_id": 1, "degrees": 0 },
  { "_id": 2, "degrees": 90 },
  { "_id": 3, "degrees": 180 },
  { "_id": 4, "degrees": 360 }
]);
```

**查询示例 **

```
db.angles.aggregate([
  { $project: {
    "radians": { $degreesToRadians: "$degrees" }
  }}
]);
```

**输出**

```
[
  { "_id": 1, "radians": 0 },
  { "_id": 2, "radians": 1.5707963267948966 },
  { "_id": 3, "radians": 3.141592653589793 },
  { "_id": 4, "radians": 6.283185307179586 }
]
```

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

要查看使用`$degreesToRadians`运算符的代码示例，请选择要使用的语言的选项卡：

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

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

async function main() {
  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 collection = db.collection('angles');

  const result = await collection.aggregate([
    { $project: {
      "radians": { $degreesToRadians: "$degrees" }
    }}
  ]).toArray();

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

main();
```

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

```
from pymongo import MongoClient

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

    result = list(collection.aggregate([
        { '$project': {
            'radians': { '$degreesToRadians': '$degrees' }
        }}
    ]))

    print(result)
    client.close()

if __name__ == "__main__":
    main()
```

------