I used a reactive function on the server to create a data frame.
And I want to express the unique vector of one column of this data frame as selectinput in the UI.
ex)
DATA<-data.frame(ID, NAME)
####server#####
DATAFRAME<-reactive({DATA[DATA$ID %in% input$ID,})
####UI######
selectizeInput("name",label="name:",choices=unique(DATAFRAME$NAME))
In other words, I want to show a list of Names for data that has been refined once by ID in advance.
In order to react to changes in the reactive expression DATAFRAME you can use an observer and update the list of names with updateSelectizeInput (as pointed out by @MrFlick).
library(shiny)
ui <- fluidPage(
titlePanel("Widget Dependencies Sample App"),
selectizeInput("IdSelect", "Choose ID", "N/A"), # IDs to select from
selectizeInput("IdName", "Choose Name", "N/A"), # Names depend on selected ID
tableOutput("IdDatatable") # show the whole data set to understand what happens
)
server <- function(input, output, session) {
ID <- paste("ID", 1:3, sep = "_")
NAME <- LETTERS[1:(3*5)]
DATA <- data.frame(ID, NAME)
updateSelectizeInput(session, "IdSelect", choices = unique(ID))
DATAFRAME <- reactive({DATA[DATA$ID %in% input$IdSelect, ]})
observe({
updateSelectizeInput(session, "IdName", choices = unique(DATAFRAME()$NAME))
})
output$IdDatatable <- renderTable(DATA)
}
shinyApp(ui = ui, server = server)
However, if you need the reactive expression DATAFRAME only once, you can make the code even simpler. In that case, you wouldn't observe a DATAFRAME that reacts to changes in a widget. You can omit the DATAFRAMEand observe the input widget directly. This observer generates a filtered vector of Names and changes the choices in the selectizeInput with only one observer.
observe({
Names <- DATA$NAME[DATA$ID %in% input$IdSelect]
updateSelectizeInput(session, "IdName", choices = unique(Names))
})
reactive()you need to add()like this :DATAFRAME()$NAMEupdateSelectInputto update the UI with the new values. See this existing question for the basic idea: stackoverflow.com/questions/46346917/…