I am learning node and now I'm trying to order an array like this:
"lng" : [{
"ES" : 5,
"EN" : 3,
"IT" : 4
}]
(This is a part of a query result in MongoDB), I need to order the array by the number:
"ES" : 5,
"IT" : 4,
"EN" : 3
I used sort() but this function orders the array alphabetically by the first parameter, but I need order by the second, I've tried a lot of things but without result.
Thank you for your help!
JavaScript has no ordered objects, so first you should transform your object to an array of this kind:
[
{ key: "ES", value: 5 },
{ key: "EN", value: 3 },
{ key: "IT", value: 4 }
]
And then sort by the value key.
You can easily do it as follows:
// ("mongoDbResult" is the variable with an object you get from MongoDB)
var result = mongoDbResult.lng;
result = Object.keys(result).map(function (key) {
return { key: key, value: result[key] };
});
And then just sort by the value key:
result.sort(function (a, b) {
return (a.value < b.value) ? -1 : 1;
});
As a result, you should get a sorted array in the result variable.
Thank you Nikita, adding the key and value the sort works perfectly, my problem now is make the query to get the results with specific key and value...
I can get the elements by the KEY:
db.users.find({"lng.key" : "ES"})
Or by the VALUE:
db.users.find({"lng.value" : 5})
But not the both at the same query :/
[EDIT]
I have find the solution, $elemMatch:
db.users.find({lng_array : {$elemMatch:{key:"ES", value:5}}})
Related
I am new at reactjs and lodash. I have an array of objects which each has many field properties. I want to change a name string value if the boolean property is true. I read thru some of the posts here, seem like .map will loop thru the array
const updatedList = this.props.oldList.map((record) => record.IsTrue === 1 ? `$({record.name} (Updated)` : record.name)
I ran the test and it did not worked at all. Instead of returning list of object with all its properities, I got the following
0: "Test1 (Updated)"
1: "Test2"
There is not object with field names and values. I was expecting the following
[
{name: "Test1 (Updated)", IsTrue: 1},
{name: "Test1", IsTrue: 0}
]
Any help with lodash is appreciated.
You can use spread syntax to return the other key and value and update the name-value where isTrue is 1.
const input = [{ name: "Test1", IsTrue: 1 }, { name: "Test1", IsTrue: 0 }],
output = input.map((record) => ({
...record,
name: record.IsTrue === 1 ? `${record.name} (Updated)` : record.name
}));
console.log(output);
So heres my mongodb document:
{
"_id" : "",
"lists" : [
{
"name" : "list 1",
"items" : []
},
{
"name" : "list 2",
"items" : []
}
]
}
How would I go about adding an object inside "items"?
This is the code I have so far, but it doesn't work:
xxx.update(_id, {$push: { "lists.$.items": item}});
Note that I have access to the index (variable called 'index'), so its possible to insert an item at index, 0, 1, 2..., etc.
I tried this before, but it won't work:
xxx.update({_id, "lists": index}, {$push: { "lists.$.items": item}});
I also looked at other similar questions and couldn't find anything. Most of them have some sort of id field in their arrays, but I don't.
What about
xxx.update({_id}, {$push: { "lists.index.items": item}});
Of course this would fail, what I mean is replace index with real index values
xxx.update({_id}, {$push: { "lists.2.items": item}});
You can manipulate the update json based on the index maybe as below.
var update = '{$push: { "lists.'+index+'.items": '+item+'}}';
var updateObj = JSON.parse(update);
xxx.update({_id}, updateObj);
Not sure if it will work as it is or it would need further tweaking, but you get the idea.
I have a problem with multiplying an array of key-value pairs in Meteor / MongoDB. I want to multiply an entire ingredient list with a fixed value. The collection looks like this:
"ingredients" : [
{
"ingredient" : "noodle",
"amount" : 500,
"unit" : "g"
},
{
"ingredient" : "cheese",
"amount" : 100,
"unit" : "g"
}
],
Now, I want to multiply the amount value with a certain number multip, let's say 1,5. The desired output would look like:
"ingredients" : [
{
"ingredient" : "noodle",
"amount" : 750,
"unit" : "g"
},
{
"ingredient" : "cheese",
"amount" : 150,
"unit" : "g"
}
],
Right now I have this:
for (i in this.ingredients){
var precalc = this.ingredients[i].amount * multip; //Here's the Multiplicator
var prez=this.ingredients[i].ingredient;
var prem=this.ingredients[i].unit;
Recipes.update(
{"_id": this._id},
{"$set": {
"ingredients":[{ingredient:prez, amount:precalc, unit:prem}]
}}
);
}
I precalculated the new value and used $set because apparently the $mul operator isn't working with meteor. This solution partly works, but unfortunately it overwrites all ingredients and only multiplies the last one (which is obvious). There must be a much simpler way to do that - I just didn't find it. I'm new to MongoDB and Meteor so any help is greatly appreciated!
Don't execute an update for each ingredient, only one for the entire document. I'd do something like this:
let newIngredients = this.ingredients.map(x => {
ingredient: x.ingredient,
amount: x.amount * 1.5,
unit: x.unit
});
Recipes.update(
{_id: this._id},
{$set: {ingredients: newIngredients}}
);
How to get subdocument element's count inside an array and how to update the subdocument's key in MongoDB
For eg, following is the whole doc stored in mongodb:
{
"CompanyCode" : "SNBN",
"EventCode" : "ET00008352",
"EventName" : "Sunburn Presents Avicii India Tour",
"TktDetail" : [
{
"Type" : "Category I",
"Qty" : {
"10-Dec" : {
"value" : 58
},
"11-Dec" : {
"value" : 83
},
"12-Dec" : {
"value" : 100
}
}
},
{
"Type" : "Category II",
"Qty" : {
"10-Dec" : {
"value" : 4
},
"11-Dec" : {
"value" : 7
},
"12-Dec" : {
"value" : 8
}
}
},
{
"Type" : "PRICE LEVEL 1",
"Qty" : {
"11-Dec" : {
"value" : 2
}
}
},
{
"Type" : "CatIV",
"Qty" : {
"18-Dec" : {
"value" : 20
}
}
}
],
"TransDate" : [
"10-Dec-2013",
"11-Dec-2013",
"12-Dec-2013",
],
"VenueCode" : "SNBN",
"VenueName" : "Sunburn",
"_id" : ObjectId("52452db273b92012c41ad612")
}
Here TktDetail is an array, inside which there is a Qty subdoc which contains multiple elements, I want to know how to get the elements count inside Qty per index?
For example, the 0th index of TktDetail array contains 1 Qty subdoc, which further has a element count of 3, whereas 3rd index has element count of 1 in Qty subdoc.
If I want to update the subdoc key, like, I want to update the date in Qty from "10-Dec" to "10-Dec-2013", how is it possible?
Thanks in advance, looking for a reply ASAP..
So the first thing here is that you actually asked two questions, being "how do I get a count of the items under Qty?" and "how can I change the names?". Now while normally unrelated I'm going to treat them as the same thing.
What you need to do is change your schema and in doing so I'm going to allow you to get the count of items and I'm going to encourage you to change those field names as well. Specifically you need a schema like this:
"TktDetail" : [
{
"Type" : "Category I",
"Qty" : [
{ "date": ISODate("2013-12-10T00:00:00.000Z") , "value" : 58 },
{ "date": ISODate("2013-12-11T00:00:00.000Z"), "value" : 83 },
{ "date": ISODate("2013-12-01T00:00:00.000Z"), "value" : 100 },
]
},
All the gory details are in my answer here to a similar question. But the problem basically is that when you use sub-documents in the way you have you are ruining your chances of doing any meaningful query operations on this, as to get at each element you must specify the full path to get there.
That answer has more detail, but the case is you really want an array. The trade-off, it's a little harder to update, especially considering you have nested arrays, but it's a lot easier to add and much easier to query.
Also, and related, change your dates to be dates and not strings. The strings, are no good for comparisons inside MongoDB. With them set as proper BSON dates (noting I clipped them to the start of day) you can compare, and query ranges and do useful things. Your application code will be happy to as the driver will return a real date object, rather than something you have to manipulate "both ways".
So once you have read through, understood and implemented this, on to counting:
db.collection.aggregate([
// Unwind the TktDetail array to de-normalize
{"$unwind": "$TktDetail"},
// Also Unwind the Qty array
{"$unwind": "$Qty" },
// Get some group information and count the entries
{"$group": {
"_id": {
"_id": "$_id,
"EventCode": "$EventCode",
"Type": "$TktDetail.Type"
},
"Qty": {"$sum": 1 }
}},
// Project nicely
{"$project": {
"_id": 0,
"EventCode": "$_id.EventCode",
"Type: "$_id.Type",
"Qty": 1,
}},
// Let's even sort it
{"$sort": { "EventCode": 1, "Qty" -1 }}
])
So that allowed us to get a count of the items in Qty for each EventCode by Type with the Qty ordered higest to lowest.
And that is not possible on your current schema without loading and traversing each document in code.
So there is the case. Now if you want to ignore this and just go about changing the sub-document key names, then you'll need to do remove the key and underlying document and replace with the new key name, using update:
db.collection.update(
{ EventCode: "ET00008352"},
{ $unset:{ "TktDetail.0.Qty.10-Dec": "" }}
)
db.collection.update(
{ EventCode: "ET00008352"},
{ $set:{ "TktDetail.0.Qty.10-Dec-2013": { value: 58 } }}
)
And you'll need to do that for every item that you have.
So you either work out that schema conversion or otherwise have a lot of work anyway in order to change the keys. For myself, I'd do it properly, and only do it once so I didn't run into the next problem later.
I have a document in MongoDB as below.
{
"CorePrice" : 1,
"_id" : 166,
"partno" : 76,
"parttype" : "qpnm",
"shipping" :
[
{
"shippingMethod1" : "ground",
"cost1" : "10"
},
{
"shippingMethod2" : "air",
"cost2" : "11"
},
{
"shippingMethod3" : "USPS",
"cost3" : "3"
},
{
"shippingMethod4" : "USPS",
"cost4" : 45
}
]
}
My goal is to add CorePrice (1) to cost4 (45) and retrieve the computed value as a new column "dpv". I tried using the below query. However I receive an error exception: $add only supports numeric or date types, not Array. I'm not sure why. Any kind of help will be greatly appreciated.
db.Parts.aggregate([
{
$project: {
partno: 1,
parttype: 1,
dpv: {$add: ["$CorePrice","$shipping.cost1"]}
}
},
{
$match: {"_id":{$lt:5}}
}
]);
When you refer to the field shipping.cost1 and shipping is an array, MongoDB does not know which entry of the shipping-array you are referring to. In your case there is only one entry in the array with a field cost1, but this can't be guaranteed. That's why you get an error.
When you are able to change your database schema, I would recommend you to turn shipping into an object with a field for each shipping-type. This would allow you to address these better. When this is impossible or would break some other use-case, you could try to access the array entry by numeric index (shipping.0.cost1).
Another thing you could try is to use the $sum-operator to create the sum of all shipping.cost1 fields. When there is only one element in the array with a field cost1, the result will be its value.
I am able to achieve this by divorcing the query into two as below.
var pipeline1 = [
{
"$unwind": "$shipping"
},
{
$project:{
partno:1,
parttype:1,
dpv:{
$add:["$CorePrice","$shipping.cost4"]
}
}
},
{
$match:{"_id":5}
}
];
R = db.tb.aggregate( pipeline );