Arrays 如何将对象前置到数组的顶部位置?
如果我在MongoDb文档中有以下数组:Arrays 如何将对象前置到数组的顶部位置?,arrays,mongodb,position,push,prepend,Arrays,Mongodb,Position,Push,Prepend,如果我在MongoDb文档中有以下数组: "example": { [ "number": 5, "someValue": "V" ], [ "number": 7, "someValue": "H" ] } 如何将下面的数组添加到上面的数组的顶部: [ "number": 3, "someValue": "S" ] 使原始数组变成: "example": { [
"example": {
[
"number": 5,
"someValue": "V"
],
[
"number": 7,
"someValue": "H"
]
}
如何将下面的数组添加到上面的数组的顶部:
[
"number": 3,
"someValue": "S"
]
使原始数组变成:
"example": {
[
"number": 3,
"someValue": "S"
],
[
"number": 5,
"someValue": "V"
],
[
"number": 7,
"someValue": "H"
]
}
您可以使用以下
$push
操作符的选项来实现这一点:
db.collection.update({},
{
$push:{
"arr":{
$each:[
{
"number": 3,
"someValue": "S"
}
],
$position: 0
}
}
})
$position
指定将插入元素的位置