Selection of columns for the table in Shiny - r

Question

I would like to add a new category at the beginning which will select the columns for the table. I can not combine variables with other elements in an application. Could someone explain to me what I'm doing wrong? As you can see on the graphics program does not work well.
My code:
library(shiny)
data <- data.frame(
Category1 = rep(letters[1:3], each = 15),
Info = paste("Text info", 1:45),
Category2 = sample(letters[15:20], 45, replace = T),
Size = sample(1:100, 45),
MoreStuff = paste("More Stuff", 1:45)
)
ui <- fluidPage(titlePanel("Test Explorer"),
sidebarLayout(
sidebarPanel(
selectizeInput(
"show_vars",
"Columns to show:",
choices = colnames(data),
multiple = TRUE,
selected = c("Category1", "Info", "Category2")
),
uiOutput("category1"),
uiOutput("category2"),
uiOutput("sizeslider")
),
mainPanel(tableOutput("table"))
))
server <- function(input, output, session) {
data2 <- reactive({
req(input$table)
if (input$table == "All") {
return(data)
}
data[, names(data) %in% input$show_vars]
})
output$category1 <- renderUI({
selectizeInput('cat1',
'Choose Cat 1',
choices = c("All", sort(as.character(
unique(data$Category1)
))),
selected = "All")
})
df_subset <- eventReactive(input$cat1, {
if (input$cat1 == "All") {
df_subset <- data
}
else{
df_subset <- data[data$Category1 == input$cat1, ]
}
})
df_subset1 <- reactive({
if (is.null(input$cat2)) {
df_subset()
} else {
df_subset()[df_subset()$Category2 %in% input$cat2, ]
}
})
output$category2 <- renderUI({
selectizeInput(
'cat2',
'Choose Cat 2 (optional):',
choices = sort(as.character(unique(
df_subset()$Category2
))),
multiple = TRUE,
options = NULL
)
})
output$sizeslider <- renderUI({
sliderInput(
"size",
label = "Size Range",
min = min(df_subset1()$Size),
max = max(df_subset1()$Size),
value = c(min(df_subset1()$Size), max(df_subset1()$Size))
)
})
df_subset2 <- reactive({
if (is.null(input$size)) {
df_subset1()
} else {
df_subset1()[df_subset1()$Size >= input$size[1] &
df_subset1()$Size <= input$size[2], ]
}
})
output$table <- renderTable({
df_subset2()
})
}
shinyApp(ui, server)

Answer 1

You have few problems with your code
You stored that reactive value of the columns selection in data2(), and displaying table df_subset2(). As with your code, the columns change when you add columns and select Cat1 dropdown, since its values are dependent on the data.react.
Avoid using generic names like data to store data. Sometimes it interfere with R base names
You need to use ObserveEvent and eventReactive, when you expect the change on UI to reflect
Below is what I fixed, you can change accordingly.
Added a submit button
Wrapped the input selections code into an ObserveEvent
By this, your data is displayed only when you click the submit button.
Here is the code.
library(shiny)
data.input <- data.frame(
Category1 = rep(letters[1:3], each = 15),
Info = paste("Text info", 1:45),
Category2 = sample(letters[15:20], 45, replace = T),
Size = sample(1:100, 45),
MoreStuff = paste("More Stuff", 1:45)
)
ui.r
ui <- fluidPage(titlePanel("Test Explorer"),
sidebarLayout(
sidebarPanel(
selectizeInput(
"show_vars",
"Columns to show:",
choices = colnames(data.input),
multiple = TRUE,
selected = c("Category1", "Info", "Category2")
),
actionButton("button", "An action button"),
uiOutput("category1"),
uiOutput("category2"),
uiOutput("sizeslider")
),
mainPanel(tableOutput("table"))
))
server.r
server <- function(input, output, session) {
data.react <- eventReactive(input$button, {
data.input[, input$show_vars]
})
observeEvent(input$button, {
output$category1 <- renderUI({
data.sel <- data.react()
selectizeInput('cat1',
'Choose Cat 1',
choices = c("All", sort(as.character(
unique(data.sel$Category1)
))),
selected = "All")
})
df_subset <- eventReactive(input$cat1, {
data.sel <- data.react()
if (input$cat1 == "All") {
data.sel
}
else{
data.sel[data.sel$Category1 == input$cat1,]
}
})
output$category2 <- renderUI({
selectizeInput(
'cat2',
'Choose Cat 2 (optional):',
choices = sort(as.character(unique(
df_subset()$Category2
))),
multiple = TRUE,
options = NULL
)
})
df_subset1 <- reactive({
if (is.null(input$cat2)) {
df_subset()
} else {
df_subset()[df_subset()$Category2 %in% input$cat2,]
}
})
output$sizeslider <- renderUI({
sliderInput(
"size",
label = "Size Range",
min = min(data.input$Size),
max = max(data.input$Size),
value = c(min(data.input$Size), max(data.input$Size))
)
})
df_subset2 <- reactive({
if (is.null(input$size)) {
df_subset1()
} else {
df_subset1()[data.input$Size >= input$size[1] &
data.input$Size <= input$size[2],]
}
})
output$table <- renderTable({
df_subset2()
})
})
}
shinyApp(ui, server)