R：带库（DT）的库（闪亮）：创建<selectinput>对于 Plot 上的不同 colors</selectinput>

Question

I am so sorry to trouble you. I am new to R programming and programming in general. 95% of the time, when search and read online examples, I fail to understand them.

I have the codes for a shiny app. I did not write these codes. These codes were given as default. When you run it, the bottom table comes up with a plot of "dots" that has no color. When you click on a specific row, the "dot" it represents turns to red.

library(shiny)

library(DT)
ui <- fluidPage(
    h3("t1"),
    tableOutput("t1"),
    hr(),
    fluidRow(
        column(9, h3("dt1"),
               dataTableOutput("dt1")),
        column(3, h3("x4"),
               verbatimTextOutput("x4"))),
    hr(),
    fluidRow(
        column(8, h3("dt2"),
               dataTableOutput("dt2")),
        column(4, h3("p5"),
               plotOutput("p5")))
)
options(error = function() traceback(2))
server <- function(input, output, session) {
    output$t1 <- renderTable(iris[1:10,], striped = TRUE, hover = TRUE)
    output$dt1 <- renderDataTable(iris, options = list( pageLength = 5))
    output$x4 <- renderPrint({
        s = input$dt1_rows_selected
        if (length(s)) {
            cat('These rows were selected:\n\n')
            cat(s, sep = ', ')
        }
    })

    output$dt2 <- renderDataTable(iris,
                                  options = list(pageLength = 5),
                                  server = FALSE)
    output$p5 <- renderPlot({
        s <- input$dt2_rows_selected
        plot(iris$Sepal.Length, iris$Sepal.Width)
        if (length(s)) {
            points(iris[s, c("Sepal.Length", "Sepal.Width"), drop = F],
                   pch = 19, cex = 1, col = "red")
        }
    })
}
shinyApp(ui, server)

The question is, how do I create selectInput for different color names, so that the user can decide which color to use and not just use the default RED color?

From my own research, I think I need to add 2 lines of code within UI and edit 1 line of code within server. Unfortunately these methods does not work though. Within UI

selectInput("color", "What is your preferred color?", choices = c("blue", "gold", "green", "pink", "red", "yellow"))
textOutput("color")

Within server changing the "red" in this code

points(iris[s, c("Sepal.Length", "Sepal.Width"), drop = F],
                       pch = 19, cex = 1, col = "red")

to "input$color"

points(iris[s, c("Sepal.Length", "Sepal.Width"), drop = F],
                           pch = 19, cex = 1, col = "input$color")

I got the error message below when I select the colors I want and attempt to color my plots (by selecting the rows in the table dt2)

invalid color name 'input$color'

So sorry to trouble all of you. I understand that most of you are busy with your own lives and I really appreciate any help or advice given.

Answer 1

The issue was that "input$color" should be input$color (no quotes).