Level replacement in R shiny creates two level lists, one with NULL

Question

I'm working for the first time on a shiny app.

Based on an uploaded xlsx, the shiny app creates an reactive output called garnetRF(). Based on the number of differently named samples in the uploaded xlsx, the app creates dynamic tabs in output$tabp. In the tabs, the user can pick a color to be displayed for each sample. So far, so good.

Now, in the ouput$setting I want to plot the results with the colors the user picked. Thus, my idea was to rename the sample levels by the picked color names (cls.0). However, when performing the code as following, two level lists are produced and I don't understand why:

output$tabp <- renderUI({
    req(garnetRF())
    l = length(unique((garnetRF()[,"sample"])))
    
    myTabs <- lapply(1:l, function(i) {
      tabPanel(title = as.list(factor(unique(garnetRF()[,"sample"])))[[i]],
               colourInput(paste0("col_", i), NULL, paste0("FF000", i), showColour = "background")
      )
    })
    do.call(tabsetPanel, myTabs)
  })
  
  output$setting <- renderPlot({
    l2 = length(unique((garnetRF()[,"sample"])))
    cls.0 = factor((garnetRF()[,"sample"]))
    levels(cls.0) = factor((sapply(1:l2, function(j){input[[paste0("col_", j)]]})))
    print(levels(cls.0))

[1] "NULL"
[1] "#FF0001" "#FF0002" "#FF0003"

I would be grateful if anyone can help me with this....

Try `req()` in output$setting as `output$setting <- renderPlot({ req(garnetRF()) l2 = length(unique((...` — YBS, Nov 23 '20 at 15:12

score 0 · Answer 1 · answered Nov 23 '20 at 15:11

0

I think the right approach is

levels(cls.0) = sapply(1:l2, function(j){input[[paste0("col_", j)]]})

since levels of a factor is just a vector of strings.

answered Nov 23 '20 at 15:11

EugenR

176
6

When using this, I get this error: Error in rep.int: invalid 'times' value – mee1988 Nov 23 '20 at 15:26
Do you have an idea how to solve this invalid 'times' value error and where it is coming from? – mee1988 Nov 23 '20 at 15:52
check out l2, maybe it is 0? – EugenR Nov 23 '20 at 15:59
l2 is 3 in this case – mee1988 Nov 23 '20 at 16:02

Level replacement in R shiny creates two level lists, one with NULL

1 Answers1