In CoffeeScript, I'm trying to test if a given string is a member of an array of strings. Here is what I have tried (note that the first attempt uses the in operator and the second one uses the of operator):
console.log list
list = [ i.courseid for i in list ]
console.log list
console.log courseid
console.log courseid in list
console.log '2904984' in list
console.log 2904984 in list
and:
console.log list
list = [ i.courseid for i in list ]
console.log list
console.log courseid
console.log courseid of list
console.log '2904984' of list
console.log 2904984 of list
The results of compiling and running both scripts is:
[ { courseid: '2904984', _id: 5243274d46f7f6d72e000001 },
{ courseid: '2484419', _id: 5245ac6ef3a459ee44000002 },
{ courseid: '2180094', _id: 5245b3fa659d2c2d45000001 },
{ courseid: '2179793', _id: 5245ca8ab405987a49000001 },
{ courseid: '2169240', _id: 5245ca8eb405987a49000002 } ]
2904984,2484419,2180094,2179793,2169240
2484419
false
false
false
Any clue as to why neither item in list or item of list returns true when the item is a member of the list?
list = [i.courseid for i in list] gives you a nested array of arrays (a 1-item array containing your array of string IDs). You want list = (i.courseid for i in list), giving you a flat array of strings as you expect.
Related
I have a very large array, similar to this one:
{
"name":"latest_test",
"value":[
{
"name":"2016-06-27-12Z",
"type":"Folder"
},
{
"name":"2016-06-28-00Z",
"type":"Folder"
},
{
"name":"2016-06-28-12Z",
"type":"Folder"
},
{
"name":"2016-06-29-00Z",
"type":"Folder"
},
{
"name":"2016-06-29-12Z",
"type":"Folder"
}
]
}
I only want to keep the items that have 2016-06-29 in their name. Such that I have a new array that only consists of 2016-06-29-00Z and 2016-06-29-12Z.
I tried to use a filter with #contains(item(), '2016-06-29') but this returns 0.
item() is the entire object for an element in the array. In order to filter on a property have to specify the property also.
Change the filter condition to
#contains(item().name, '2016-06-29')
This query works perfectly
{
$or:[{author:this.userId} , {somethingelse:true} ]
}
But when I try:
{
$or:[{author:this.userId} , {sharedwith[this.userId]:true} ]
}
I receive the message
Errors prevented startup:
While processing files with ecmascript (for target os.linux.x86_64): server/main.js:113:43: Unexpected token, expected
, (113:43)
=> Your application has errors. Waiting for file change.
And thats where the comma , in the $or statement is
Help
I guess that you are trying to retrieve all documents for which the current user is the author, or which have been shared with him/her? And therefore that you have structured your documents with a sharedWith field which is a hash map of userId as keys and boolean as value?
Document structure:
{
author: string,
sharedWith: {
<userId1>: boolean
// <userId2>…
}
}
In that case, your MongoDB query should use the dot notation to specify the value of a nested field within sharedWith field:
{
$or: [{
author: string
}, {
"sharedWith.<userId>": boolean
}]
}
To easily create the query with the interpolated value of <userId>, you can use a computed key in your object (ES6 syntax):
{
$or:[{
author: this.userId
} , {
// The query computed key must be in square brackets.
// Specify the field child key using the dot notation within your query.
["sharedwith." + this.userId]: true
}]
}
Or with good old ES5 syntax, similarly to #MichelFloyd's answer:
var query = {
$or: [{
author: this.userId
}]
};
var newCondition = {};
newCondition["sharedWith." + this.userId] = true;
query.$or.push(newCondition);
Note: the above described document structure could conveniently replace the sharedWith hash map by an array (since having a false value for the boolean could simply be replaced by removing the corresponding userId from the array):
{
author: string,
sharedWith: [
<userId1>
// <userId2>…
]
}
In which case the query would simply become:
{
$or:[{
author: this.userId
} , {
// In MongoDB query, the below selector matches either:
// - documents where `sharedWith` value is a string equal to
// the value of `this.userId`, or
// - documents where `sharedWith` value is an array which contains
// an element with the same value as `this.userId`.
sharedwith: this.userId
}]
}
Try building the query as a variable before running it.
let query = { $or: [{ author: this.userId }]};
const sw = sharedwith[this.userId];
query.$or.push({sw: true});
MyCollection.find(query);
So I have found quite few related posts on SO on how to update a field in a sub array, such as this one here
What I want to achieve is basically the same thing, but updating a field in a subarray dynamically, instead of just calling the field name in the query.
Now I also found how to do that straight in the main object, but cant seem to do it in the sub array.
Code to insert dynamically in sub-object:
_.each(data.data, function(val, key) {
var obj = {};
obj['general.'+key] = val;
insert = 0 || (Documents.update(
{ _id: data._id },
{ $set: obj}
));
});
Here is the tree of what I am trying to do:
Documents: {
_id: '123123'
...
smallRoom:
[
_id: '456456'
name: 'name1'
description: 'description1'
],
[
...
]
}
Here is my code:
// insert a new object in smallRoom, with only the _id so far
var newID = new Mongo.ObjectID;
var createId = {_id: newID._str};
Documents.update({_id: data._id},{$push:{smallRooms: createId}})
And the part to insert the other fields:
_.each(data.data, function(val, key) {
var obj = {};
obj['simpleRoom.$'+key] = val;
console.log(Documents.update(
{
_id: data._id, <<== the document id that I want to update
smallRoom: {
$elemMatch:{
_id : newID._str, <<== the smallRoom id that I want to update
}
}
},
{
$set: obj
}
));
});
Ok, having said that, I understand I can insert the whole object straight away, not having to push every single field.
But I guess this question is more like, how does it work if smallRoom had 50 fields, and I want to update 3 random fields ? (So I would NEED to use the _each loop as I wouldnt know in advance which field to update, and would not want to replace the whole object)
I'm not sure I 100% understand your question, but I think the answer to what you are asking is to use the $ symbol.
Example:
Documents.update(
{
_id: data._id, smallRoom._id: newID._str
},
{
$set: { smallroom.$.name: 'new name' }
}
);
You are finding the document that matches the _id: data._id, then finding the object in the array smallRoom that has an _id equal to newId._str. Then you are using the $ sign to tell Mongo to update that object's name key.
Hope that helps
I have a very big problem when im trying to access objects in array in mongoDB.
First I'm finding where id key has a value of "mens" in my database collection "categories":
mongodb.db().collection("categories").find({id: "mens"}).toArray(function(err, data) {
console.log(data);
}
When i try to output the result in the console, it shows me this :
[ { _id: 5172d1daffdd81f3234d5f88,
categories: [ [Object], [Object] ],
id: 'mens',
name: 'Mens',
page_description: 'Men\'s range. Hard-wearing boots, jackets and clothing for unbeatable comfort day in, day out.
headed.',
page_title: 'Men\'s Footwear, Outerwear, Clothing & Accessories',
parent_category_id: 'root',
c_showInMenu: true } ]
But when I try to get for example name or page_title with this :
mongodb.db().collection("categories").find({id: "mens"}).toArray(function(err, data) {
console.log(data.page_title);
}
It returns UNDEFINED ! ! !
The data returned is an array, so you need to access the object in the array as data[0].page_title i.e.
mongodb.db().collection("categories").find({id: "mens"}).toArray(function(err, data) {
console.log(data[0].page_title); // prints "Men's Footwear, Outerwear, Clothing & Accessories"
}
Given a collection with documents like this:
Task Collection document
[
{
"_id"=>BSON::ObjectId('54d674b64d42504b6a000000'),
"submissions"=>
[{"_id"=>BSON::ObjectId('54d674b64d42504b6a010000'),
"grade"=>nil,
"user_id"=>BSON::ObjectId('54d1e2454d42503069060000')},
{"_id"=>BSON::ObjectId('54d674b64d42504b6a020000'),
"grade"=>nil,
"user_id"=>BSON::ObjectId('54d1e2454d42503069070000')},
{"_id"=>BSON::ObjectId('54d674b64d42504b6a030000'),
"grade"=>nil,
"user_id"=>BSON::ObjectId('54d1e2454d42503069080000')}
],
},
{
"_id"=>BSON::ObjectId('54d674b64d42504b6a100000'),
"submissions"=>
[{"_id"=>BSON::ObjectId('54d674b64d42504b6a010000'),
"grade"=>5,
"user_id"=>BSON::ObjectId('54d1e2454d42503069060000')},
{"_id"=>BSON::ObjectId('54d674b64d42504b6a020000'),
"grade"=>7,
"user_id"=>BSON::ObjectId('54d1e2454d42503069070000')},
{"_id"=>BSON::ObjectId('54d674b64d42504b6a030000'),
"grade"=>nil,
"user_id"=>BSON::ObjectId('54d1e2454d42503069080000')}
],
},
{
"_id"=>BSON::ObjectId('54d674b64d42509b6a000000'),
"submissions"=>
[{"_id"=>BSON::ObjectId('54d674b64d42504b6a010000'),
"grade"=>8,
"user_id"=>BSON::ObjectId('54d1e2454d42503069060000')},
{"_id"=>BSON::ObjectId('54d674b64d42504b6a020000'),
"grade"=>7,
"user_id"=>BSON::ObjectId('54d1e2454d42503069070000')},
{"_id"=>BSON::ObjectId('54d674b64d42504b6a030000'),
"grade"=>6,
"user_id"=>BSON::ObjectId('54d1e2454d42503069080000')}
],
}
]
How can I get all the tasks documents whose submissions array contains no nil grade?
The result in the example would contain just the last one.
I am using Mongoid, but I welcome a pure Mongodb query too.
Using elem_match and a negative comparison:
Task.where(:submissions.elem_match => { :grade.ne => nil })