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。
$setEquals
Amazon DocumentDB 中的$setEquals運算子用於判斷兩組是否相等。它會比較兩個陣列，如果true它們包含相同的不同元素，則無論它們的順序為何，都會傳回 。
參數
-
expression1：要比較的第一個陣列。
-
expression2：要比較的第二個陣列。
範例 (MongoDB Shell)
下列範例示範運算$setEquals子用來比較兩組值的使用情況。
建立範例文件
db.collection.insertMany([
{ _id: 1, fruits: ["apple", "banana", "cherry"] },
{ _id: 2, fruits: ["banana", "apple", "cherry"] },
{ _id: 3, fruits: ["apple", "banana", "orange"] }
])
查詢範例
db.collection.find({
$expr: {
$setEquals: ["$fruits", ["apple", "banana", "cherry"]]
}
})
輸出
{ "_id" : 1, "fruits" : [ "apple", "banana", "cherry" ] }
{ "_id" : 2, "fruits" : [ "banana", "apple", "cherry" ] }
查詢使用 $setEquals運算子來比較每個文件fruits的欄位與陣列 ["apple", "banana", "cherry"]。傳回 fruits 欄位等於比較陣列的文件。
程式碼範例
若要檢視使用 $setEquals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 collection = db.collection('mycollection');
// Insert sample documents
await collection.insertMany([
{ _id: 1, fruits: ["apple", "banana", "cherry"] },
{ _id: 2, fruits: ["banana", "apple", "cherry"] },
{ _id: 3, fruits: ["apple", "banana", "orange"] }
]);
// Query using $setEquals
const result = await collection.find({
$expr: {
$setEquals: ["$fruits", ["apple", "banana", "cherry"]]
}
}).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['mycollection']
# Insert sample documents
collection.insert_many([
{"_id": 1, "fruits": ["apple", "banana", "cherry"]},
{"_id": 2, "fruits": ["banana", "apple", "cherry"]},
{"_id": 3, "fruits": ["apple", "banana", "orange"]}
])
# Query using $setEquals
result = list(collection.find({
"$expr": {
"$setEquals": ["$fruits", ["apple", "banana", "cherry"]]
}
}))
print(result)
client.close()
example()
