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。

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

`$pull` 運算子用於從陣列中移除符合指定條件之值的所有執行個體。當您需要從文件中的陣列欄位中移除特定元素時，此運算子非常有用。

**參數**
+ `field`：要從中移除值的陣列欄位名稱 (s)。
+ `value`：決定要從陣列中移除哪個元素的值或條件 (s)。

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

下列範例示範如何使用 `$pull`運算子從陣列欄位移除元素。

**建立範例文件**

```
db.restaurants.insertMany([
  {
    name: "Pizza Hut",
    cuisine: "Italian",
    features: ["Delivery", "Takeout", "Dine-in"]
  },
  {
    name: "Sushi Saito",
    cuisine: "Japanese",
    features: ["Dine-in", "Private Dining"]
  },
  {
    name: "Taco Bell",
    cuisine: "Mexican",
    features: ["Delivery", "Takeout", "Drive-thru"]
  }
])
```

**查詢範例**

```
db.restaurants.updateMany(
  { cuisine: "Italian" },
  { $pull: { features: "Takeout" } }
)
```

**輸出**

```
{
  "acknowledged" : true,
  "matchedCount" : 1,
  "modifiedCount" : 1
}
```

上述查詢會從`cuisine`欄位為「義大利文」的所有文件中移除「擷取」功能。

## 程式碼範例
<a name="pull-code"></a>

若要檢視使用 `$pull`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 updateRestaurants() {
  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 restaurants = db.collection('restaurants');

  await restaurants.updateMany(
    { cuisine: 'Italian' },
    { $pull: { features: 'Takeout' } }
  );

  const updatedRestaurants = await restaurants.find({}).toArray();
  console.log(updatedRestaurants);

  await client.close();
}

updateRestaurants();
```

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

```
from pymongo import MongoClient

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

    result = restaurants.update_many(
        { 'cuisine': 'Italian' },
        { '$pull': { 'features': 'Takeout' } }
    )

    updated_restaurants = list(restaurants.find({}))
    print(updated_restaurants)

    client.close()

update_restaurants()
```

------