翻译或纠错本页面
- Reference >
- Operators >
- Update Operators >
- Array Update Operators >
- $each
$each¶
- $each¶
The $each modifier is available for use with the $addToSet operator and the $push operator.
Use the $each modifier with the $addToSet operator to add multiple values to an array <field> if the values do not exist in the <field>.
db.collection.update( <query>, { $addToSet: { <field>: { $each: [ <value1>, <value2> ... ] } } } )
Use the $each modifier with the $push operator to append multiple values to an array <field>.
db.collection.update( <query>, { $push: { <field>: { $each: [ <value1>, <value2> ... ] } } } )
Examples¶
Use $each with $push Operator¶
The following example appends each element of [ 90, 92, 85 ] to the scores array for the document where the name field equals joe:
db.students.update(
{ name: "joe" },
{ $push: { scores: { $each: [ 90, 92, 85 ] } } }
)
Use $each with $addToSet Operator¶
A collection inventory has the following document:
{ _id: 2, item: "cable", tags: [ "electronics", "supplies" ] }
Then the following operation uses the $addToSet operator with the $each modifier to add multiple elements to the tags array:
db.inventory.update(
{ _id: 2 },
{ $addToSet: { tags: { $each: [ "camera",
"electronics",
"accessories" ] } } }
)
The operation adds only "camera" and "accessories" to the tags array since "electronics" already exists in the array:
{ _id: 2,
item: "cable",
tags: [ "electronics", "supplies", "camera", "accessories" ] }