Call the UI of R built-in functions - r

Question

I want to be able to design a set of UI that can call R's built-in functions, but the current problem lies in the data selection when calling the function. I need to return the calculation result of a function to my UI interface so that another function can be arbitrary Select the variables in the current environment as the input of the function. This is my current code. Can anyone give me some suggestions or some cases?
library(shiny)
function_choose = c("sin","cos")
ui <- fluidPage(
selectInput('f', 'function_choose', function_choose,
selected = function_choose[[1]]),
sidebarPanel(
conditionalPanel(condition = "input.f=='sin'",
mainPanel(
selectInput('sin_dat','data',c("I want to show all the variables in the workspace here ")),
actionButton(inputId = "sin_run",label = "RUN")
)
),
conditionalPanel(condition = "input.f=='cos'",
mainPanel(
selectInput('workspace','data',c("I want to show all the variables in the workspace here "))),
actionButton(inputId = "cos_run",label = "RUN")
)
),
mainPanel(
textOutput("text")
)
)
server <- function(input, output,session) {
data <- c(0.1,0.2,0.3)
observeEvent(input$sin_run,{
data_sined <- sin(data)
output$text <- renderText({
"data_sined is created"
})
})
observeEvent(input$cos_run,{
data_cosed<- cos(data)
output$text <- renderText({
"data_cosed is created"
})
})
}
shinyApp(ui = ui, server = server)

Answer 1

I changed the logic of your app to make it less complicated, I hope this is still ok for your purpose. We can use ls() to get a character vector of all variables in the global (or any other) environment. If we define a vector function_choose in the global environment, then this will be available too. We could easily circumvent this by defining the choices argument inside selectInput or by specifying a names pattern that is selected by ls(). Once we have selected a variable, the input$data returns a character vector. To access the underyling data based on a character vector we use get().
library(shiny)
function_choose = c("sin","cos")
shinyApp(
ui = fluidPage(
sidebarPanel(
selectInput('f', 'function_choose', choices = function_choose,
selected = function_choose[1]),
selectInput('data','data', choices = ls()),
actionButton(inputId = "run",label = "RUN")
),
mainPanel(
textOutput("text")
)
),
server = function(input, output,session) {
res <- eventReactive(input$run, {
dat <- get(input$data)
switch(input$f,
sin = sin(dat),
cos = cos(dat)
)
})
output$text <- renderText({
res()
})
})