i have array of objects like such :
var chart = [
{
"IDACCT": 28,
"LVLCOA": 2,
"IDPRNT": 1,
"NMACCI": "110-000 - ASSETS"
},
{
"IDACCT": 76,
"LVLCOA": 2,
"IDPRNT": 1,
"NMACCI": "170-000 - FIXED ASSETS"
}
];
i would like to return object where my search (predicate) is based using two keys :
d = _.filter(chart,function(o,e){
return o.LVLCOA === 2 && o.IDPRNT === e
});
this doesnt' work. i need to provide maybe some argument to the function. the problem e is not recognize in the function.
Of course it doesn't when you try to compare a number to an undeclared variable e. I guess you wanted to compare it to another number?
In your particular case, you can just setup a chain with two filter() calls and do away with predicate functions entirely. Passing filter() object shorthands should be sufficient:
var e = 1;
var d = _(chart)
.filter({ LVLCOA: 2 })
.filter({ IDPRNT: e })
.value();
Related
So i am really stuck with this exercise for a few hours. The idea is to find the friends name who is also studying the weakest subject. I have this piece of code here:
const reportCard = {
Biology: 85,
English: 75,
Economics: 90,
History: 67,
Philosophy: 98,
};
const subjects = {
Dylan: 'Biology',
Jen: 'English',
Emily: 'Economics',
Amy: 'History',
Lenny: 'Philosophy',
};
console.log(studyBuddy(reportCard, subjects));
I have implemented a min variable to find the lowest grades in first object like so:
val = Object.values(reportCard)
const min = Math.min(...val)
How can i match the second object values with the first one that match the min variable. Is it anyway that i can implement that?
I just want a hint i don't want that somebody to solve it for me.
I will try to help you without actually solving the task.
I would first take keys of the friends object, go through them and use as a key to access reportCard object. Let me give you a quick example:
const studentNames = Object.keys(subjects); // all student names
studentNames.forEach(student => {
const subjectValue = reportCard[student]; // now you have the value for every student
});
Assuming the max value for subject is 100, you can define variable equal to 101 at first step, and check it in the loop if any of the student has less value. I hope that will help.
I implemented it like this:
const studyBuddy = (reportCard, subjects) => {
// Write code here
val = Object.values(reportCard)
const min = Math.min(...val)
const weakestSubject = Object.keys(reportCard).find(key => reportCard[key] === min);
for (let val in subjects){
if (subjects[val] === weakestSubject){
return val
} else {
return 'Me'
}
}
};
The challenge criteria is actually to return the friends name, else to return string 'Me'. I don't know why it is returning me? When i delete the else statement it actually returns the right name. What's wrong?
Idea is to get the weakest subject name from the object 'reportCard'; you can loop through the object, mark the subject which has the lowest marks.
Now, after getting the lowest marks from the object 'reportCard', again loop through the second object 'subjects' to check who is assigned to the subject, which has lowest marks we obtained by a loop through the object 'reportCard'.
const reportCard = {
Biology: 85,
English: 75,
Economics: 90,
History: 67,
Philosophy: 98,
};
const subjects = {
Dylan: 'Biology',
Jen: 'English',
Emily: 'Economics',
Amy: 'History',
Lenny: 'Philosophy',
};
function studyBuddy(reportCard, subjects){
var weakestSubjectName = null;
var min = Number.MAX_VALUE;
for(var key in reportCard){
// check every marks whether it is lowest than the prev lowest marks or not
// if so, assign the subject name which has currently lowest marks
if(reportCard[key] < min){
min = reportCard[key];
weakestSubjectName = key;
}
}
// now you can loop through the second object, to get the name of person/friend who's studying the subject
for(var key in subjects){
if(subjects[key] === weakestSubjectName) return key;
}
return null;
}
console.log(studyBuddy(reportCard, subjects));
I have a UI like this:
Where I can
Enter something in search box
Drag users from table to chart
The logic required is:
Initially chart shows some subset of all users (e.g., first 10)
When users are dragged on chart they are added to the users that already there
When filter is applied all users are removed from chart and then it is repopulated with some subset of matching users
I am trying to implement such logic with RxJs.
I have filteredUsers$ and addedUsers$ stream that produce users matching filter and dragged users correspondingly.
I need to combine them in such way:
Observable
.<OPERATOR>(filteredUsers$, addedUsers$)
.subscribe(([filteredUsers, addedUsers]) => {
// When filteredUsers$ fires:
// filteredUsers is value from stream
// addedUsers == null
// When addedUsers$ fires:
// filteredUsers is latest available value
// addedUsers is value from stream
redrawChart(/* combining users */)
});
Any ideas how I can achieve this?
Time sequence:
Filtered: - a - - - - a - ->
Added : - - b - b - - - ->
Result : - a ab - ab - a - ->
If you want the final stream to be populated only when addUsers$ fires with latest from could be a solution:
So, in your case addUsers$ could be the first stream.
You can try out the following code:
let firstObservable$ = Observable.from([1, 2, 3, 4])
.zip(Observable.interval(50), (a, b) => {
return a;
});
let secondObservable$ = Observable.from([5, 6])
.zip(
Observable.interval(70), (a, b) => {
return a;
});
firstObservable$
.withLatestFrom(secondObservable$, (f, s) => ({ a: f, b: s }))
.subscribe(x => {
console.log('result: ', x);
});
The first observable emits every 50 ms a value from the array.
The second observable every 75 ms.
The values printed are {a: 2, b: 5} {a: 3, b: 6} {a: 4, b: 6}
Because 1 was emitted before 5 we lose the pair (1,5)!
I am not clear but missing a pair from addUsers$ if the other stream has not emitted may be non-desired behavior for you.
You could overcome that if you start the second stream with an initial value and then filter out any results you don't want.
You have the combineLatest operator which basically does what you are describing. It combines two observables and gives you the latest value of both streams.
So:
--a--b-----c---
-x-----d-----p-
-combineLatest-
--a--b-b---c-c
x x d d p
This should allow you to do what you want if I understand correctly.
Here's the official doc link:
https://github.com/Reactive-Extensions/RxJS/blob/master/doc/api/core/operators/combinelatest.md
Eventually I have done it by adding additional subject:
var filteredUsers$ = ... // users from filter
var addedUsers$ = ... // users dragged on chart
var usersToDraw$ = new Subject();
subscriptions:
usersToDraw$
.subscribe(usersToDraw => {
redrawChart(usersToDraw);
});
filteredUsers$
.subscribe(filteredUsers => {
usersToDraw$.next(filteredUsers);
});
Observable
.combineLatest(filteredUsers$, addedUsers$)
.filter(([filteredUsers, addedUsers]) => addedUsers != null)
.subscribe(([filteredUsers, addedUsers]) => {
// we 'clear' stream so the same users won't be added twice
addedUsers$.next(null);
usersToDraw$.next(/* combining users */);
});
UPDATE
The solution can be improved with withLatestFrom (thanks #nova)
usersToDraw$
.subscribe(usersToDraw => {
redrawChart(usersToDraw);
});
filteredUsers$
.subscribe(filteredUsers => {
usersToDraw$.next(filteredUsers);
});
addedUsers$
.withLatestFrom(filteredUsers$)
.subscribe(([addedUsers, filteredUsers]) => {
usersToDraw$.next(/* combining users */);
});
JSBIN Sample
I have a changeable set of child components (POJO object) that each have its own state stream. Each time a user triggers addChild/removeChild/clearChildren, a new set of children state streams is emitted with #switchMap. So far so good! (And so amazed by RxJS!)
With Rx.Observable.from(arrayOfStateStreams).combineAll() I get a good result as long as the arrayOfStateStreams isn't an empty array.
Since this is a partial state that is combined(Latest) on a higher level, I need to get an empty array emitted or the global state tree will contain old state data that is no longer true!
I can emit some reserved token like ['EMPTY-ARRAY-PLACEHOLDER-TOKEN'], but that's just weird.
A better way would be to always append one last stream into the array so the last index can be considered trash. Still confusing code and state though.
Using [null] is not OK, since we could have a child state of 'null'.
Anyone who can solve this in a good way? Can't this be supported since there should be no other representation of an empty array after #combineAll?
Credits go to github user trxcllnt who provided the following answer:
combineAll won't emit unless the combined Observables emit at least
one value, but you could check to ensure the collection you're
combining is empty or not, and either combine or emit an empty Array:
var arrayOfStreamsStream = Rx.Observable
.of(
[], [
Rx.Observable.of('blah-1'), // component state.
Rx.Observable.of('blah-2'),
Rx.Observable.of('blah-3')
], [], [
Rx.Observable.of('foo-1'),
Rx.Observable.of('qux-2')
]
)
.switchMap(function onMap(coll) {
return coll.length === 0 ?
Observable.of(coll) :
Observable.combineLatest(...coll);
})
.subscribe(function onSubscribe(data) {
console.log('onSubscribe START')
console.dir(data)
console.log('onSubscribe END')
})
This has nothing to do with combineAll. The problem is that Observable.from results in nothing (an empty observable) when passed an empty array.
The only viable solution that I can think of if you have to get a result from an empty array is to return something else in that case.
Ann example to illustrate the problem and a possible solution.
var data = [1, 2, 3, 4, 5];
log('With data: ');
Rx.Observable.from(data)
.subscribe(function (d) { log('data: ' + d); });
// Prints:
// With data:
// data: 1
// data: 2
// data: 3
// data: 4
// data: 5
var data = [];
log('Without data: ');
var nullDataObject = { msg: 'my null data object' };
Rx.Observable.from(data.length == 0 ? [nullDataObject] : data)
.subscribe(function (d) { log('data: ' + d); });
// Prints:
// With data:
// data: [object Object]
Runnable example on jsfiddle.
When consuming this you simply filter away the object representing an empty array where appropriate.
a possible workaround is to just pipe it with startWith();
combineLatest(potentiallyEmptyArray).pipe(
startWith<any>([])
);
Note: Similar issues exist with combineLatest() (the static version) which can be solved using defaultIfEmpty() - which works, but it screws up the typing of the output.
// array of Observables
const animals: Observable<{ species: 'dog' | 'cat' }>[] = [];
// Type '{ species: "dog" | "cat"; }[]' is not assignable to type 'never[]'.
combineLatest(animals).pipe(defaultIfEmpty([]));
In TypeScript you need to either know the type of the object or use <any>[] which means you then lose typing completely.
If you have a concrete type you can use one of these:
defaultIfEmpty<Animal[]>([])
defaultIfEmpty([] as Animal[])
I often don't have a concrete type for the return value of an observable. So I came up with an operator:
export const emptyArrayIfEmpty = () => <T>(observable: Observable<T[]>) =>
observable.pipe(defaultIfEmpty([] as T[]));
Then I can add the following and get out an empty array if animals === [] without losing any typing information:
combineLatest(animals).pipe(emptyArrayIfEmpty());
I have a spreadsheet that I update on a regular basis. I also have to re-sort the spreadsheet when finished because of the changes made. I need to sort with multiple criteria like the below settings. I have searched for examples but my Google search skills have failed me.
Sort range from A1:E59
[x] Data has header rows
sort by "Priority" A > Z
then by "Open" Z > A
then by "Project" A > Z
Mogsdad's answer works fine if none of your cells have values automatically calculated via a formula. If you do use formulas, though, then that solution will erase all of them and replace them with static values. And even so, it is more complicated than it needs to be, as there's now a built-in method for sorting based on multiple columns. Try this instead:
function onEdit(e) {
var priorityCol = 1;
var openCol = 2;
var projectCol = 3;
var sheet = SpreadsheetApp.getActiveSheet();
var dataRange = sheet.getDataRange();
dataRange.sort([
{column: priorityCol, ascending: true},
{column: openCol, ascending: false},
{column: projectCol, ascending: true}
]);
}
Instead of making a separate function, you can use the built-in onEdit() function, and your data will automatically sort itself when you change any of the values. The sort() function accepts an array of criteria, which it applies one after the other, in order.
Note that with this solution, the first column in your spreadsheet is column 1, whereas if you're doing direct array accesses like in Mogsdad's answer, the first column is column 0. So your numbers will be different.
That is a nice specification, a great place to start!
Remember that Google Apps Script is, to a large extent, JavaScript. If you extend your searching into JavaScript solutions, you'll find plenty of examples of array sorts here on SO.
As it happens, much of what you need is in Script to copy and sort form submission data. You don't need the trigger part, but the approach to sorting can be easily adapted to handle multiple columns.
The workhorse here is the comparison function-parameter, which is used by the JavaScript Array.sort() method. It works through the three columns you've indicated, with ascending or descending comparisons. The comparisons used here are OK for Strings, Numbers and Dates. It could be improved with some cleaning up, or even generalized, but it should be pretty fast as-is.
function sortMySheet() {
var sheet = SpreadsheetApp.getActiveSheet();
var dataRange = sourceSheet.getDataRange();
var data = dataRange.getValues();
var headers = data.splice(0,1)[0]; // remove headers from data
data.sort(compare); // Sort 2d array
data.splice(0,0,headers); // replace headers
// Replace with sorted values
dataRange.setValues(data);
};
// Comparison function for sorting two rows
// Returns -1 if 'a' comes before 'b',
// +1 if 'b' before 'a',
// 0 if they match.
function compare(a,b) {
var priorityCol = 0; // Column containing "Priority", 0 is A
var openCol = 1;
var projectCol = 2;
// First, compare "Priority" A > Z
var result = (a[priorityCol] > b[priorityCol] ) ?
(a[priorityCol] < b[priorityCol] ? -1 : 0) : 1;
if (result == 0) {
// "Priority" matched. Then compare "Open" Z > A
result = (b[openCol] > a[openCol] ) ?
(b[openCol] < a[openCol] ? -1 : 0) : 1;
}
if (result == 0) {
// "Open" matched. Finally, compare "Project" A > Z
result = (a[projectCol] > b[projectCol] ) ?
(a[projectCol] < b[projectCol] ? -1 : 0) : 1;
}
return result;
}
Try this using the Apps Script sort instead of the native JavaScript. I had the same issue with sorting the header row(s) and this solved the issue.
So I think something like this should work:
function onOpen() {
SpreadsheetApp.getActiveSpreadsheet()
.getSheetByName("Form Responses 1").sort(2);
}
Regarding sorting by multiple columns, you can chain that sort() method, with the final sort() having the highest priority, and the first sort() the lowest. So something like this should sort by Start date, then by End date:
function onOpen() {
SpreadsheetApp.getActiveSpreadsheet()
.getSheetByName("Form Responses 1").sort(3).sort(2);
}
Reference link:-
https://support.google.com/docs/thread/16556745/google-spreadsheet-script-how-to-sort-a-range-of-data?hl=en
Not sure if this is still relevant, but you can use the sort() function to define another tab as a sorted version of the original data.
Say your original data is in a tab named Sheet1; I'm also going to act as though your Priority, Open, and Project columns are A, B, and C, respectively.
Create a new tab, and in cell A1 type:
=sort(Sheet1!A1:E59, 1, TRUE, 2, FALSE, 3, TRUE)
The first argument specifies the sheet and range to be sorted, followed by three pairs: the first of each pair specifies the column (A=1, B=2, etc.), and the second specifies ascending (TRUE) or descending (FALSE).
I'm trying to implement cascading controls using the following LINQ query expression.
The idea is that I have three option lists represented by the tables OptionA, OptionB and OptionC and a view called OptionIndex with one column each for OptionA_ID, OptionB_ID, OptionC_ID and that table has of all the combinations of tags from the option lists that are in use. Left outer joining the OptionIndex on the option list produces a boolean for the Disabled attributed in the option tag.
How do I make the on clause, which is .Where(...) in the following sample code, allow for any combination of the controls being used?
For example, lets say the user initially selects option value 123 in OptionA. The code to return the Values, Labels and Disabled booleans for OptionC would look like the following:
from t1 in OptionCs
from t2 in OptionIndexes.Where(x => t1.OptionC_ID == x.OptionC_ID && new List<int> { 123 }.Contains(x.OptionA_ID)).DefaultIfEmpty()
group new {t1, t2} by new { t1.OptionC_ID, t1.Label } into g
select new { g.Key.OptionC_ID, g.Key.Label, Disabled = g.Count(t => t.t2.OptionC_ID == null) > 0 }
Then lets say the user selects option values 456 and 789 in OptionB. The code to return the Values, Labels and Disabled booleans for OptionC change to:
from t1 in OptionCs
from t2 in OptionIndexes.Where(x => t1.OptionC_ID == x.OptionC_ID && new List<int> { 123 }.Contains(x.OptionA_ID) && new List<int> { 456, 789 }.Contains(x.OptionB_ID)).DefaultIfEmpty()
group new {t1, t2} by new { t1.OptionC_ID, t1.Label } into g
select new { g.Key.OptionC_ID, g.Key.Label, Disabled = g.Count(t => t.t2.OptionC_ID == null) > 0 }
To make the example code easier to understand I used new List<int>. In the actual project, however I would be passing the integers from the option list in as integer arrays from the controls themselves.
The trick is somehow making the query expression dynamic so that it can represent any combination of 0 to N multi-select controls being used or passing something that tells the join to accept any value for any given control such as
{x.OptionB_ID.Any}.Contains(x.OptionB_ID)
What is the best way to handle this?
Thanks!
Distilling your issue down to a simple example, consider this list of integers:
List<int> l = new List<int> { 1, 25, 3, 99, -23, 0, 15, 75 };
Say that you want to conditionally filter this list based on external criteria. Sometimes you want positive numbers, sometimes you want numbers smaller than 50, sometimes you want numbers divisible by 5, or any combination of these. Applying all filters with a static expression would look like this:
l.Where(n => n > 0).Where(n => n < 50).Where(n => n % 5 == 0);
To apply any or all of these dynamically, just build the LINQ query in pieces:
// These switches simulate your external conditions.
bool conditionA = true;
bool conditionB = false;
bool conditionC = true;
IEnumerable<int> myList = l;
if (conditionA) { myList = myList.Where(n => n > 0 ); }
if (conditionB) { myList = myList.Where(n => n < 50 ); }
if (conditionC) { myList = myList.Where(n => n % 5 == 0); }
With the switches set as in my example, the output is 25, 15, 75.
Side note: if you are not aware of it, use LINQPad to experiment with things like this. It is a fantastic tool for essentially executing code interactively, be it LINQ code or not. When I built the above sample, I inserted myList.Dump(); calls after each of the last 4 lines so I could see how each filter was applied. Here is the output: