This is going to sound very weird but it will make the code for this app very compact.
Is there a way to call a .operator conditionally. Here is an example
say I have a class with three values that I can do a . on.
class A {
int intOne;
int intTwo;
int intThree;
}
to get the intOne in class A you can do A.intOne right....
but what if you you wanted the string at the right of the . to conditionally be there.
A."conditionalvariable"
so if a user clicks a button say button A then the conditional variable will be A.intOne.
and if the user clicks button b then the value of "conditionalvariable" will be intTwo and therefore you will be getting the data.
please assume that I am not stupid, and I am needing this exact thing for a specific use case. If you post an answer that is not this exact solution it will not be accepted.
example:
var a;
switch (name) {
case "intOne":
a = A.intOne;
break;
...
}
//this is not an acceptable answer
I realize that this would be an "answer" to this question, but it actually isn't I need the exact thing stated because I am using streams.
here is that use case I was talking about. I could explain away all day as to why I need it this way, but either way this either does exist or doesn't so a simple no this doesn't exist is an acceptable answer.
return StreamProvider.value(
value: classDataNotif.homework,
)
based on what is clicked before this widget the "homework" will need to change to "notes", or "tests".
You cannot do a switch above this because it will be calling the stream to early and cause the widget to crash. doing a switch inside the widget and copying code over would defeat the purpose. in order to make the code as compact and as easy to write as possible i need the string at the right of the . operator to change.
thanks in advance :)
Related
I'm creating a very simple Access database with a table and corresponding form. For some questions on the form, I'd like to disable following questions, or hide them using branching logic.
For example, in my form I have a combobox question that asks: Are you a smoker? - "Yes", "No", "Prefer not to answer". The following question is: If yes, how often do you smoke? If they chose the answers "No" or "Prefer not to answer" for the first question, then I don't want the second question to be visible/enabled.
I've been searching for a way to do this and the easiest way seems to be setting the Visible property of textbox "If yes, how often do you smoke?" to No. After that, I go to question "Are you a smoker?" and go to Event Procedure in the Properties menu. This brings up a VBA code editor with the following text:
Option Compare Database
Private Sub Text969_Click()
End Sub
Private Sub Combo367_Click()
End Sub
I've been looking at different pages but I can't seem to get the code to work. For the particular question I'm asking, the name of the form is "Chronic Smokers" and the field for the first question is named "Are you a smoker." and the second question is named "If yes, how often." This is the code I've been trying and it doesn't work, but I can't seem to figure anything else out:
Option Compare Database
Private Sub Text969_Click()
End Sub
Private Sub Combo367_Click()
If Chronic Smokers.Combo367='Yes' then
Chronic Smokers.If yes, how often.Visible = True
Else
Chronic Smokers.If yes, how often.Visible = False
End if
End Sub
I think part of my problem is that I don't know the way the naming conventions or syntax for this code works. I have a feeling part of the problem is that I have blank spaces without underscores in the names If anybody can help me out with this, I'd really appreciate it!
VBA code could be as simple as Me.[how often].Visible = Me.Combo367 = "Yes". No If Then Else needed. Code will need to be in combobox AfterUpdate as well as form Current events, not Click event. Code will apply to ALL instances of control, not just the current record.
NOTE: use of Me qualifier is shorthand for form/report object code is behind.
If you prefer to use If Then Else, correct syntax would be:
With Me
If .Combo367 = "Yes" Then
.[how often].Visible = True
Else
.[how often].Visible = False
End if
End With
Suggest you explore Conditional Formatting. It allows to enable/disable textboxes and comboboxes dynamically per record without VBA. Controls will still be visible but 'greyed out'.
And yes, strongly advise not to use spaces nor punctuation/special characters (underscore is only exception) in naming convention nor reserved words as names. If you do, then enclose in [ ] as shown above. Better naming would be ChronicSmokers and HowOften. And give objects more meaningful names than the defaults assigned by Access.
While end-to-end testing our app, I am often waiting for a state transition (a modal to close, a button to appear, etc). Blind experimentation has led me to sometimes use browser.wait(ExpectedConditions.presenceOf(someElement), and other times use browser.wait(someElement.isPresent()).
To me, the names imply they're interchangeable. But it isn't so. Is there something about the situations in which I use these that will help me tell which to use when?
In my experience, I have used element.isPresent() for when I do not want to specifically verify something. For example I can write:
element.isPresent().then(function(elm){
if(elm) { //if the element is present, do something }
else { //if the element is not present, do something else }
});
But if I need some element to be present/visible/clickable in order to execute an expect or something else, then I would use a browser.wait(EC.presenceOf/visibilityOf/elementToBeClickable(element))
It also depends on the element you need to wait for. If its a button that you need to click, you'll have to use elementToBeClickable
If we take a look at the code, we will see that isPresent method looks like this
isPresent(): wdpromise.Promise<boolean> {
return this.count().then((count) => {
return count > 0;
});
}
While presenceOf is dependent on isPresent
presenceOf(elementFinder: ElementFinder): Function {
return elementFinder.isPresent.bind(elementFinder);
};
In fact they are doing the same. But note, that ExpectedConditions operators, like not, or and etc. expecting ExpectedConditions function as an argument whichpresenceOf is, while isPresent is not.
Sometimes you need more complicated conditions, than to check that one particular element is present browser.wait(someElement.isPresent()). This is where ExpectedConditions constructions are incredibly useful and this is where you would need presenceOf.
Ok, I've been stuggling with this one for a while, and have spent a lot of time trying different things to do something that I have done very easily using PHP.
I am trying to iterate over a list while keeping track of a variable locally, while spitting out HTML attempting to populate a table.
Attempt #1:
#{
var curDate : Date = null
for(ind <- indicators){
if(curDate == null || !curDate.equals(ind.getFirstFound())){
curDate = ind.getFirstFound()
<tr><th colspan='5' class='day'>#(ind.getFirstFound())</th></tr>
<tr><th>Document ID</th><th>Value</th><th>Owner</th><th>Document Title / Comment</th></tr>
}
}
}
I attempt too user a scala block statement to allow me to keep curDate as a variable within the created scope. This block correctly maintains curDate state, but does not allow me to output anything to the DOM. I did not actually expect this to compile, due to my unescaped, randomly thrown in HTML, but it does. this loop simply places nothing on the DOM, although the decision structure is correctly executed on the server.
I tried escaping using #Html('...'), but that produced compile errors.
Attempt #2:
A lot of google searches led me to the "for comprehension":
#for(ind <- indicators; curDate = ind.getFirstFound()){
#if(curDate == null || !curDate.equals(ind.getFirstFound())){
#(curDate = ind.getFirstFound())
}
<tr><th colspan='5' class='day'>#(ind.getFirstFound())</th></tr>
<tr><th>Document ID</th><th>Value</th><th>Owner</th><th>Document Title / Comment</th></tr>
}
Without the if statement in this block, this is the closest I got to doing what I actually wanted, but apparently I am not allowed to reassign a non-reference type, which is why I was hoping attempt #1's reference declaration of curDate : Date = null would work. This attempt gets me the HTML on the page (again, if i remove the nested if statement) but doesn't get me the
My question is, how do i implement this intention? I am very painfully aware of my lack of Scala knowledge, which is being exacerbated by Play templating syntax. I am not sure what to do.
Thanks in advance!
Play's template language is very geared towards functional programming. It might be possible to achieve what you want to achieve using mutable state, but you'll probably be best going with the flow, and using a functional solution.
If you want to maintain state between iterations of a loop in functional programming, that can be done by doing a fold - you start with some state, and on each iteration, you get the previous state and the next element, and you then return the new state based on those two things.
So, looking at your first solution, it looks like what you're trying to do is only print an element out if it's date is different from the previous one, is that correct? Another way of putting this is you want to filter out all the elements that have a date that's the same date as the previous one. Expressing that in terms of a fold, we're going to fold the elements into a sequence (our initial state), and if the last element of the folded sequence has a different date to the current one, we add it, otherwise we ignore it.
Our fold looks like this:
indicators.foldLeft(Vector.empty[Indicator]) { (collected, next) =>
if (collected.lastOption.forall(_.getFirstFound != next.getFirstFound)) {
collected :+ next
} else {
collected
}
}
Just to explain the above, we're folding into a Vector because Vector has constant time append and last, List has n time. The forall will return true if there is no last element in collected, otherwise if there is, it will return true if the passed in lambda evaluates to true. And in Scala, == invokes .equals (after doing a null check), so you don't need to use .equals in Scala.
So, putting this in a template:
#for(ind <- indicators.foldLeft(Vector.empty[Indicator]) { (collected, next) =>
if (collected.lastOption.forall(_.getFirstFound != next.getFirstFound)) {
collected :+ next
} else {
collected
}
}){
...
}
In my current project I have to deal with more complex forms. Fields (i'll name them 'A' and 'B') are automatically filled if a specific field (i'll name that one 'C') received user input. But also if the user inputs data into field A, the fields B and C are automatically filled out.
(This is only a simple example, the current logic is a bit more complicated)
What I have to take care of is that no cycles happen (C -> A -> C -> A -> ...). So I need to now if the current value change was due to user input or another field that had received input and then triggered the value change of the current field. And I also need to now in the second case which field exactly triggered the value change because then I must trigger other specific actions corresponding from who/what triggered that value change.
Is there a general approach in Vaadin to deal with this kind of form
structure? The problem at the moment is that I simply don't now who
or what triggered what ValueChangeEvent.
Are there frameworks to deal with this or am I overlooking an existing Vaadin pattern?
Handling of valueChange events in Vaadin is a bit of pain, since it always fires, no matter if the user has changed something, or the application has used setValue(....) on the component.
The only solution for this is to remember when you do a setValue(....) in your application and then disable the trigger code in the other components.
For example in this case (endless loop):
field1.addValueChangeListener( field2.setValue('Updated by field1');
field2.addValueChangeListener( field1.setValue('Updated by field2');
Change it that way:
boolean inTrigger= false;
field1.addValueChangeListener(
{
if (!inTrigger)
{
inTrigger= true;
field2.setValue('Updated by field1');
inTrigger= false;
}
});
field2.addValueChangeListener(
{
if (!inTrigger)
{
inTrigger= true;
field1.setValue('Updated by field2');
inTrigger= false;
}
});
That way you can prevent update loops and let execute your code exactly once.
I have a model that predicts, based on multiple variables like income and marital status, whether a person is credit worthy (yes/no).
My question is whether it is possible to create a visual tool where you enter the value of each of the variables and then the tool gives you a YES or NO if it predicts this person is credit worthy.
I have seen something like this before and I think it was made with Shiny. However, I cannot find it anymore.
Any help or tips would be very appreciated!
Bert
Code a function mymodel(a,b,c,d....) where a:d are your variables, and it returns TRUE or FALSE based on credit worthiness.
In your UI, use the widgets found here: http://shiny.rstudio.com/tutorial/lesson3/ to pass values to the input object.
Then, you can use:
shinyServer(
function(input, output) {
output$text1 <- renderText({
if(mymodel(input$widget1,input$widget2,...)) {
"Credit-Worthy"
} else {
"Not Credit-Worthy"
}
})
}
)
Make sure in your UI, you then pass:
mainPanel(
textOutput("text1")
)
As found in http://shiny.rstudio.com/tutorial/lesson4/
This will give you a text output of a individuals credit-worthiness. If you want to have other visual effects, you can use the same if statement above to pass different themes/images/etc.. to output.