本文為英文版的機器翻譯版本，如內容有任何歧義或不一致之處，概以英文版為準。

# \$1not
<a name="not-aggregation"></a>

`$not` 彙總運算子會對表達式執行邏輯 NOT 操作。`true` 如果表達式評估為 `false`，且`false`如果表達式評估為 ，則傳回 `true`。

**參數**
+ `expression`：要否定的表達式。

## 範例 (MongoDB Shell)
<a name="not-aggregation-examples"></a>

下列範例示範如何使用 `$not`運算子反轉布林值。

**建立範例文件**

```
db.users.insertMany([
  { _id: 1, name: "Alice", active: true },
  { _id: 2, name: "Bob", active: false },
  { _id: 3, name: "Charlie", active: true }
]);
```

**查詢範例**

```
db.users.aggregate([
  {
    $project: {
      name: 1,
      active: 1,
      inactive: { $not: ["$active"] }
    }
  }
]);
```

**輸出**

```
[
  { _id: 1, name: 'Alice', active: true, inactive: false },
  { _id: 2, name: 'Bob', active: false, inactive: true },
  { _id: 3, name: 'Charlie', active: true, inactive: false }
]
```

## 程式碼範例
<a name="not-aggregation-code"></a>

若要檢視使用`$not`彙總運算子的程式碼範例，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 collection = db.collection('users');

  const result = await collection.aggregate([
    {
      $project: {
        name: 1,
        active: 1,
        inactive: { $not: ["$active"] }
      }
    }
  ]).toArray();

  console.log(result);
  await 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']
    collection = db['users']

    result = list(collection.aggregate([
        {
            '$project': {
                'name': 1,
                'active': 1,
                'inactive': { '$not': ['$active'] }
            }
        }
    ]))

    print(result)
    client.close()

example()
```

------