I had shared original collection example, current my output, and expected output. with link of mongo playground. original collection:
[
{
"_id": "foo1",
"1": {
"bar": 6
},
"0": {
"bar": 11
},
"3": {
"bar": 8
},
"2": {
"bar": 0
},
"5": {
"bar": 8
},
"4": {
"bar": 19
},
"6": {
"bar": 8
}
},
{
"_id": "foo2",
"1": {
"bar": 18
},
"0": {
"bar": 3
},
"3": {
"bar": 19
},
"2": {
"bar": 0
},
"5": {
"bar": 13
},
"4": {
"bar": 17
},
"7": {
"bar": 8
},
"6": {
"bar": 8
},
"8": {
"bar": 8
}
},
{
"_id": "foo3",
"1": {
"bar": 0
},
"0": {
"bar": 2
},
"3": {
"bar": 18
},
"2": {
"bar": 2
},
"4": {
"bar": 12
}
}
]
current output is
[
{
"_id": {
"2": 2
}
},
{
"_id": {
"5": 21
}
},
{
"_id": {
"4": 48
}
},
{
"_id": {
"8": 8
}
},
{
"_id": {
"1": 24
}
},
{
"_id": {
"0": 16
}
},
{
"_id": {
"3": 45
}
},
{
"_id": {
"7": 8
}
},
{
"_id": {
"6": 16
}
}
]
expected output
[
{
"2": 2
},
{
"5": 21
},
{
"4": 48
},
{
"8": 8
},
{
"1": 24
},
{
"0": 16
},
{
"3": 45
},
{
"7": 8
},
{
"6": 16
}
]
link of example: https://mongoplayground.net/p/Eh9psmEhgIk
I am junior developer, I had tried with other ways, but I am stuck in middle, I request please help me to explore this exercise. How can I improve better or other way that I can achieve my expected output.
CodePudding user response：
You are missing only one step: $replaceRoot
{$replaceRoot: {newRoot: "$_id"}}
See how it works on the playground example
CodePudding user response：
Maybe something like this:
{
"$replaceRoot": {
"newRoot": "$_id"
}
}