How to retain the curves after plotting in R Shiny? - r

Question

I am building a Shiny app, where the user can add different curves to the plot, but I can't make the plot to retain the already added curves. How can I make that happen?
In the simplified reproducible code below are altogether 8 curve possibilities, based on 3 radiobuttons selections which have 2 options each. I would like to keep these as radiobuttons and not use checkboxes, as in my real app that I am working on there will be about 300 combinations that would be too confusing to use with checkboxes. Please see the code below:
library(shiny)
library(plotly)
library(dplyr)
data111 <-data.frame("x"=1:10, "y"=c(99,98,97,96,95,94,93,92,91,90))
data112 <-data.frame("x"=5:14, "y"=c(79,78,77,76,75,74,73,72,71,70))
data121 <-data.frame("x"=9:18, "y"=c(59,58,57,56,55,54,53,52,51,50))
data122 <-data.frame("x"=3:12, "y"=c(49,48,47,46,45,44,43,42,41,40))
data211 <-data.frame("x"=7:16, "y"=c(29,28,27,26,25,24,23,22,21,20))
data212 <-data.frame("x"=11:20, "y"=c(19,18,17,16,15,14,13,12,11,10))
data221 <-data.frame("x"=2:11, "y"=c(95,94,93,92,91,90,89,88,87,86))
data222 <-data.frame("x"=1:10, "y"=c(45,44,43,42,41,40,39,38,37,36))
ui <- fluidPage(
titlePanel("Curve selection"),
sidebarLayout(
sidebarPanel(
radioButtons(inputId = "option",
label="Choose the option",
choices=c("option1"=1,
"option2"=2),
selected = 1),
radioButtons(inputId = "type",
label="Choose the type",
choices=c("type1"=1,
"type2"=2),
selected = 1),
radioButtons(inputId = "group",
label="Choose the group",
choices=c("group1"=1,
"group2"=2),
selected = 1),
actionButton("add","Add curve to the plot")
),
mainPanel(
plotlyOutput("plot")
)
)
)
server <- function(input, output) {
data <- eventReactive(input$add,{
get(paste0("data",input$option,input$type, input$group))
})
output$plot <- renderPlotly({
data <- data()
p <-plot_ly(type = "scatter", mode="lines")
p<-add_data(p, data) %>% add_trace(p, x= ~x, y = ~y)
p
})
}
shinyApp(ui = ui, server = server)
I expect that the user can choose the option, type and group in the radiobutton selections, then add the curve. After that, make a new selection of option, type and group and add the new curve to the already existing one in the plot. The user should be able to do this several times. Do you know how this can be achived?
Thanks!

Answer 1

You will have to use a reactiveValues object, in which you save already added traces.
Then you can use add_trace with a for loop for example:
I changed your eventReactive to an observeEvent, which appends the new data to the reactiveValues list.
To prevent plotting the same object twice, I created a reactiveValues usedData object, which will save the plot legend names. If the name is already at hand, nothing will be added to the plot.
server <- function(input, output) {
d <- reactiveValues(a=NULL, name=NULL)
usedData <- reactiveValues(d = NULL)
data <- observeEvent(input$add,{
src = paste0("data",input$option,input$type, input$group)
var <- get(src)
if (src %in% usedData$d) {
print("Data is already plotted")
req(F)
}
if (is.null(d$a)) {
d$a <- list(var)
d$name = list(src)
usedData$d <- src
} else {
d$a <- append(d$a, list(var))
d$name = append(d$name, list(src))
usedData$d <- append(usedData$d, src)
}
})
output$plot <- renderPlotly({
req(d$a)
data <- d$a
names = d$name
p <- plot_ly(data = data[[1]], type = "scatter", mode="lines")
if (length(data) == 1) {
p <- add_trace(p, x= ~x, y = ~y, name = names)
} else {
for (i in 1:length(data)) {
d <- data[[i]]
p <- add_trace(p, data = d, x= ~x, y = ~y, type = "scatter", mode="lines", name = names[[i]])
}
}
p
})
}