So, I have a default Immutable List:
var someObject = Immutable.Map({
myList: Immutable.List([4,5,6,7])
})
Now, I allow a person to overwrite this list, but I still need it to be contained within "someObject". Basically, if a user supplies an array, we replace what is in myList, with this "new List". I tried to accomplish like so, no luck.
basically, if this newList exists, use it - if not, either reset the myList to itself or ignore.
//example
var newList = [44444,99999]
someObject.get('myList')
.clear()
.set('myList', newList || someObject.get('myList'))
This is impossible, because the objects supplied by immutable.js are immutable - that's their point.
Instead of trying to mutate someObject, one way to accomplish what you're trying to do would be to define a defaultList = Immutable.List(4, 5, 6, 7) and then build someObject after the user has input their list. Something along the lines of
if (userList) {
someObject = Immutable.Map({myList: Immutable.List(userList)})
} else {
someObject = Immutable.Map({myList: Immutable.List(defaultList)})
}
Related
is there anyway to make a query in MongoDB using a JSON and returning a object if one field of the json matches with some in the database?
for example, I have the this object called keysArray
{ house: 'true', garden: 'false' }
and I would like to make a query in Mongo passing this object as a query field and return if some object in my database matches with at least one of those fields :
keysArray.forEach(function(key){
collection.find({keysArray}, function(err, propertyMatch){
console.log(propertyMatch)
})
})
I got no objects back, even if I have one object in my database that matches these fields.
Thanks in advance
...and I would like to make a query in Mongo passing this object as a
query field and return if some object in my database matches with at
least one of those fields.
It sounds like OR logic - if I understood it well.
On this specific case it's not possible to pass in JSON-like object to query as it would be a implicit AND logic condition.
So you should build first a OR expression and use it in collection.find(), something like this:
var myjson = {'status': 32, 'profile': {$exists: false}};
function build_logic_or(json) {
var orExpr = [];
for (var field in json) {
var expr = {};
expr[field] = json[field];
orExpr.push(expr);
}
return {'$or': orExpr};
}
It would build an expression like this:
{"$or":[{"status":32},{"profile":{"$exists":false}}]}
So:
db.collection.find(build_logic_or(myjson))
Hello I'm attempting delete a certain index in my array while using Angular2 and Typescript. I would like to retrieve the index from the value.
My array is declared normally...
RightList = [
'Fourth property',
'Fifth property',
'Sixth property',
]
I start out with a basic premise to set up my remove function.
removeSel(llist: ListComponent, rlist:ListComponent){
this.selectedllist = llist;
console.log(JSON.stringify(this.selectedllist)); // what is to be searched turned into a string so that it may actually be used
My console.log of my JSON.Stringify tells me that the value that I will attempt to remove is "Sixth property". However when I attempt to look for this value in my array using the following code. It returns -1 which means my value is not found in the array.
var rightDel = this.RightList.indexOf((JSON.stringify(this.selectedllist))); // -1 is not found 1 = found
console.log(rightDel);
On my output to the console it does return the item that is to be searched for but does not find the item in the array
CONSOLE OUTPUT:
"Sixth property" // Item to be searched for
-1 // not found
Is there something wrong in my implementation of my function that searches the array?
Of course indexOf will not find you item in array because
JSON.stringify(this.selectedllist) !== this.selectedllist
This is because JSON stringified string encodes quotes around literal, that original string doesn't have. It is easy to test:
var a = 'test';
console.log( JSON.stringify(a), a, JSON.stringify(a) === a )
Remove JSON.stringify and it should work. In general, to cast something to String type you should use its .toString() method, or simply wrap this something into String(something).
I'm trying to save the parameters used to sort a sequence in Scala for deferred execution at a later time.
For example, instead of "list.sortBy (.value)", I want to save the (".value") sort function, and retrieve this sort function ("_.value") at a later time for the actual sorting.
How do I save and retrieve the sort function arguments for deferred execution? Here is some sample test code:
class SortTest {
def testSort () = {
val myClass = new MyClass(0)
val list = List (myClass, new MyClass(1), new MyClass(2), new MyClass(3), new MyClass(4))
// Want to sort by value attribute, but don't want to sort right away. Rather
// how do I save the sort function, and retrieve it at a later time for execution?
list.sortBy(_.value)
// save the sort function (i.e. sort by the value attribute of myClass)
// something similar to the following syntax
myClass.setSortFunction (_.value)
// retrieve the sort function and sort the list
list.sortBy(myClass.getSortFunction())
}
class MyClass (d:Int){
val value = d
val sortFunc = null
// what should be the signature of this function ?
def setSortFunction (sortFunc: ()) = {
this.sortFunc = sortFunc
}
// what should be the return type of this function?
def getSortFunction () = {
return sortFunc
}
}
}
You could do something like this:
val sortFunction = (x : { def value: Int } ) => x.value
At this point, you might not be happy with the hardcoding of Int. Unfortunately, a function must have well defined types, so I cannot make this generic on the return type.
One could instead make it a definition:
def sortFunction[T] = (x : { def value: T } ) => x.value
However, you cannot pass definitions around, only values, and values cannot be parameterized.
On the other hand, you are approaching this the wrong way -- there's an assumption there that sortBy takes a function as a parameter, and only that. Not true: sortBy takes two parameters: a function, and an Ordering. If you don't save the ordering, you cannot sort it.
And here we get to the other problem... the function must have a type MyClass => T, and the ordering must be of type Ordering[T]. Without knowing in advance what T is, you cannot save that.
Fortunately, and the reason why Ordering is a good idea, you can simply create an Ordering[MyClass], and use that!
Here's how:
class MyClass(d: Int) {
val value = d
private var sortFunction: Ordering[MyClass] = _
def setSortFunction[T : Ordering](f: MyClass => T) {
sortFunction = Ordering by f
}
def getSortFunction = sortFunction
}
And you use it like this:
list.sorted(myClass.getSortFunction)
Notice that instead of sortBy it uses sorted. The method sortBy is implemented by creating an Ordering and calling sorted with it, so you are not losing any performance.
I have a class called Table that is linked to a clip on the stage.
During setup I create many Table instances and pass each one an instance of a TableData class. This TableData object includes an ID value.
I put a selection of my Table objects in an Array which I would lik eto sort based on the ID value within each Table's instance of TableData.
What I had hoped to use was something like: myArray.sortOn("tableData.id");
This doesn't seem to work and I assume that Array.sortOn() can't drill down into child clips.
Is there a way that I can achieve this?
The Array and generic Vector.<> collections both provide an alternate form of the .sort() method which takes a function. You can provide your own sorting implementation, in this case which peeks objects and compares only specific pieces of them.
Consider the following class:
class TableData {
public var ID:String;
public function TableData(id:String):void {
this.ID = id;
}
}
This is a simplified version of your TableData class that only provides a ID. Then a simplified Table class:
class Table {
private var _data:TableData;
public function get data():TableData {
return _data;
}
public function Table(tableData:TableData) {
_data = tableData;
}
}
Finally, lets put them to use, and spin up a new collection.
var list:Vector.<Table> = new Vector.<Table>();
list.push(new Table(new TableData("X")));
list.push(new Table(new TableData("C")));
list.push(new Table(new TableData("S")));
list.push(new Table(new TableData("A")));
Now, we need to make a new function that will actually do our comparison:
private function sortUsingDataID(a:Table, b:Table):int {
var aID:String = a.data.ID;
var bID:String = b.data.ID;
return aID < bID ? aID == bID ? 0 : -1 : 1;
}
This function will expect to get two items, and should return either -1, 0, or 1. If a should come before b then the function should return -1. Otherwise, if a should come after b, then it should return 1. Lastly, if the two are the same, then it should return a value of 0.
So, now we just need to tell the array to resort itself using our custom sorting function by calling .sort and passing in our function.
list.sort(sortUsingDataID);
Now the list should be sorted the way that you want.
See an working example here.
See the documentation for more details
In an C# ASP.Net MVC project, I'm trying to make a List<string> from a LINQ variable.
Now this might be a pretty basic thing, but I just cannot get that to work without using the actual column names for the data in that variable. The thing is that in the interests of trying to make the program as dynamic as possible, I'm leaving it up to a stored procedure to get the data out. There can be any amount of any which way named columns depending on where the data is fetched from. All I care about is taking all of their values into a List<string>, so that I can compare user-input values with them in program.
Pointing to the columns by their names in the code means I'd have to make dozens of overloaded methods that all just basically do the same thing. Below is false non-functioning code. But it should open up the idea of what I mean.
// call for stored procedure
var courses = db.spFetchCourseInformation().ToList();
// if the data fails a check on a single row, it will not pass the check
bool passed = true;
foreach (var i in courses)
{
// each row should be cast into a list of string, which can then be validated
// on a row-by-row basis
List courseRow = new List();
courseRow = courses[i]; // yes, obviously this is wrong syntax
int matches = 0;
foreach (string k in courseRow)
{
if (validator.checkMatch(courseRow[k].ToString()))
{
matches++;
}
}
if (matches == 0)
{
passed = false;
break;
}
}
Now below is an example of how I currently have to do it because I need to use the names for the columns
for (int i = 0; i < courses.Count; i++)
{
int matches = 0;
if (validator.checkMatch(courses[i].Name))
matches++;
if (validator.checkMatch(courses[i].RandomOtherColumn))
matches++;
if (validator.checkMatch(courses[i].RandomThirdColumn))
matches++;
if (validator.checkMatch(courses[i].RandomFourthColumn))
matches++;
/* etc...
* etc...
* you get the point
* and one of these for each and every possible variation from the stored procedure, NOT good practice
* */
Thanks for help!
I'm not 100% sure what problem you are trying to solve (matching user data to a particular record in the DB?), but I'm pretty sure you're going about this in slightly the wrong fashion by putting the data in a List. I
t should be possible to get your user input in an IDictionary with the key being used for the column name, and the object as the input data field.
Then when you get the data from the SP, you can get the data back in a DataReader (a la http://msmvps.com/blogs/deborahk/archive/2009/07/09/dal-access-a-datareader-using-a-stored-procedure.aspx).
DataReaders are indexed on column name, so if you run through the keys in the input data IDictionary, you can check the DataReader to see if it has matching data.
using (SqlDataReader reader = Dac.ExecuteDataReader("CustomerRetrieveAll", null))
{
while (reader.Read())
{
foreach(var key in userInputDictionary.AllKeys)
{
var data = reader[key];
if (data != userInputDictionary[key]) continue;
}
}
}
Still not sure about the problem you are solving but, I hope this helps!
A little creative reflection should do the trick.
var courses = db.spFetchCourseInformation()
var values = courses.SelectMany(c => c.GetType().GetProperties() // gets the properties for your object
.Select(property => property.GetValue(c, null))); // gets the value of each property
List<string> stringValues = new List<string>(
values.Select(v => v == null ? string.Empty : v.ToString()) // some of those values will likely be null
.Distinct()); // remove duplicates