append to output?

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Adrian Duşa

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Jan 26, 2015, 2:06:01 AM1/26/15
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Just curious... is it possible to preserve the "old" output and to append the new one?
Right now, the output gets recreated each time, but it would be nice to see the changes between two consecutive runs.

Best,
Adrian

Adrian Duşa

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Jan 26, 2015, 11:31:08 AM1/26/15
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I think I've solved this by using capture.output() and store individual results in a global object via <<-
The million dollar question, now, is: how do I force the <pre> tag to scroll down automatically?

It would be easy using a Javascript code like:
$(".mypre").animate({ scrollTop: $('.mypre').height() }, "fast");

But can I send Javascript commands via server.R?

Thanks,
Adrian

Adrian Duşa

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Jan 26, 2015, 3:51:34 PM1/26/15
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Got it.
For anyone needing something similar, I've simply added a custom Javascript code linked to the UI button firing the output:

$(document).ready(function(){

    $("#goButton").click(function(e){
      $('#result').animate({
        scrollTop: $('#result')[0].scrollHeight
      }, 1000);
    });

})

Works like magic.

Joe Cheng

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Jan 26, 2015, 6:34:36 PM1/26/15
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Cool. You can also accumulate results over time using Hadley's shinySignals package:

randomLetter <- reactive({
  invalidateLater(1000, session)
  sample(LETTERS, 1)
})

randomLetters <- shinySignals::reducePast(randomLetter, c, NULL)

This creates a randomLetters reactive whose return value is an ever-growing list of letters. I use this technique in the new "crandash" demo:



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Adrian Duşa

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Jan 27, 2015, 5:38:34 AM1/27/15
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Oh that's wonderful, will certainly check this out.
(glad that other people already thought about it, saves time and gives ideas).
Best,
Adrian
--
Adrian Dusa
University of Bucharest
Romanian Social Data Archive
Soseaua Panduri nr.90
050663 Bucharest sector 5
Romania

Inzirio

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Nov 23, 2015, 6:31:46 AM11/23/15
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hello, 

i'm interested in this magic trick... could you please explain me better how to link the code to the button?

it'd be great if you can create a reproducible example to use! ^^

Thank you very much!
inzirio

Adrian Dușa

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Nov 23, 2015, 1:44:22 PM11/23/15
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It all depends whether you want a standard shiny app or a custom one.
My application is highly customized, which means that I have a normal HTML page with a lot of Javascript code, and the example I mentioned has nothing to do with shiny, it's pure Javascript.
I could provide an example with HTML and Javascript, but I wouldn't know how to replicate that using standard shiny.

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Inzirio

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Nov 23, 2015, 4:11:58 PM11/23/15
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yes i know that it's javascript... but, i'm trying to understand how to put that javascript attached to the button using R code...

anyway, even the HTML+javascript, cause i'm noob with it, is a good example to have... you can send me a private message, if you prefer!

Thank you very much!! ^^

inzirio

Adrian Dușa

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Nov 23, 2015, 4:49:53 PM11/23/15
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Right, but that doesn't have anything to do with shiny, then.
It's a simple matter of defining a button with something like this, in the body:

<input id="goButton" type="button" value="clickme" />

Then use the mentioned code, in the external javascript file which needs to be mentioned in the <head> part:

$(document).ready(function(){

    $("#goButton").click(function(e){
      $('#result').animate({
        scrollTop: $('#result')[0].scrollHeight
      }, 1000);
    });

})

If you don't understand how this works, there are many examples and tutorials on W3Schools.
I hope it helps,
Adrian

Inzirio

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Nov 24, 2015, 6:23:24 AM11/24/15
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Good!
I'm wondering if there is a way to create an actionButton of a specific class in R, and then in an external CSS associate that specific javascript code...

Thank you very much! 
inzirio

Adrian Dușa

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Nov 24, 2015, 7:28:57 AM11/24/15
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Package htmlwidgets, perhaps?

Inzirio

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Nov 24, 2015, 8:30:50 AM11/24/15
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it seems a good way to do it!!!

I'll try! Thank you again! ^^

inzirio
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