I want to create a button that generates a random number and save all random numbers on my server that I can evaluate that data later.
Unfortunately I am not able to generate a vector with all random numbers. Somehow a for loop is not working. Thanks!
library(shiny)
ui <- fluidPage(
actionButton("button", "Show")
)
server <- function(input,output) {
eventReactive(input$button, {
counter <- sample(1:10,1)
})
}
shinyApp(server = server, ui = ui)
You don't need a for loop in R to generate a vector of random numbers, there are many functions for random number generation, please check here for some examples.
Here is a sample code:
library(shiny)
ui <- shinyUI(fluidPage(
titlePanel("Random number generator"),
sidebarLayout(
sidebarPanel(
sliderInput("rangeSl", "Range", min = 0,
max = 100, value = c(40, 60)
),
numericInput("num", "Quantity:", 20, min = 1, max = 100, width = "40%"),
actionButton("generateBt", "Generate Numbers")
),
mainPanel(
verbatimTextOutput("result")
)
)
))
server <- shinyServer(function(input, output) {
output$result <- renderPrint({
if (input$generateBt > 0 )
isolate(
floor(runif(input$num, min = input$rangeSl[1], max = input$rangeSl[2]))
)
})
})
shinyApp(ui = ui, server = server)
Related
As an extension of this example:
https://shiny.rstudio.com/gallery/creating-a-ui-from-a-loop.html
Say you would like the for loop to be of a length determined by a numeric input. So for example, extending the linked example (using just the second part of it):
ui <- fluidPage(
title = 'Creating a UI from a dynamic loop length',
sidebarLayout(
sidebarPanel(
# Determine Length of Loop
numericInput(inputId = "NumLoop", "Number of Loops", value = 5, min = 1, max = 5, step = 1)
),
mainPanel(
# UI output
lapply(1:input.NumLoop, function(i) {
uiOutput(paste0('b', i))
})
)
)
)
server <- function(input, output, session) {
reactive({
lapply(1:input$NumLoop, function(i) {
output[[paste0('b', i)]] <- renderUI({
strong(paste0('Hi, this is output B#', i))
})
})
})
}
shinyApp(ui = ui, server = server)
As far as I can tell there are two problems with the code:
In the UI, I don't know how to legitimately use the input from NumLoop in the for loop of the UI output. I have experimented with the conditionalPanel function with no luck.
In the server, once I put the loop behind a reactive function to make use of input$NumLoop I no longer have access to those renderUI outputs in the UI.
Any ideas of how to solves these issues would be much appreciated.
This should do the trick, as per #Dean, yes the second renderUI shouldn't be there
library(shiny)
ui <- fluidPage(
title = 'Creating a UI from a dynamic loop length',
sidebarLayout(
sidebarPanel(
# Determine Length of Loop
numericInput(inputId = "NumLoop", "Number of Loops", value = 5, min = 1, max = 10, step = 1)
),
mainPanel(
# UI output
uiOutput('moreControls')
)
)
)
server <- function(input, output, session) {
output$moreControls <- renderUI({
lapply(1:input$NumLoop, function(i) {
strong(paste0('Hi, this is output B#', i),br())
})
})
}
shinyApp(ui = ui, server = server)
I am trying to create a conditional UI in Shiny that depends on the input of a user. I specifically want to do the if in the UI part and NOT in the server part.
Here is an example of what I aim to accomplish.
# app.R
library(shiny)
ui <- shiny::fluidPage(
shiny::headerPanel(title = "Basic App"),
shiny::sidebarPanel(
shiny::sliderInput(inputId = "a",
label = "Select an input to display",
min = 0, max = 100, value = 50
)
),
if(output$out < 50){
shinyjs::hide(shiny::mainPanel(h1(textOutput("text"))))
}else{
shiny::mainPanel(h1(textOutput("text")))
}
)
server <- function(input, output) {
output$text <- shiny::renderText({
print(input$a)
})
var <- shiny::reactive(input$a)
output$out <- renderText({ var() })
}
shiny::shinyApp(ui = ui, server = server)
Is there a way that I can use the reactive value in the UI part of the function?
I think conditionalPanel could be a good solution for what you want to do
library(shiny)
ui <- shiny::fluidPage(
shiny::headerPanel(title = "Basic App"),
shiny::sidebarPanel(
shiny::sliderInput(inputId = "a",
label = "Select an input to display",
min = 0, max = 100, value = 50
)
),
shiny::mainPanel(
conditionalPanel(
condition = "input.a > 50",
h1(textOutput("text")))
)
)
server <- function(input, output) {
output$text <- shiny::renderText({
print(input$a)
})
}
shiny::shinyApp(ui = ui, server = server)
Hope this helps!!
I have a very simple app which fails. The reason it fails is that the reactive dataset is available solely within the observeEvent function but not outside. I use observeEvent to get datasets from two different sources wrangled. For this example I simply used cbind. My actual code is much more complicated.
This is a logical / syntax related problem but all my searching came up short. In essence I want merged_data() to be available for all parts of the app.
Minimum repr example - this fails because merged_data() is not available outside of the ObserveEvent.
library(shiny)
library(shinyjs)
library(DT)
# Define UI for application that draws a histogram
ui <- fluidPage(
# Application title
titlePanel("testing 1 2 3"),
# Sidebar with a slider input for number of bins
sidebarLayout(
sidebarPanel(
),
# Show a plot of the generated distribution
mainPanel(
fluidRow(
column(width = 2,
offset = 0,
align = "center",
actionButton(inputId = "fetch_data_inputId",
label = "data")
) #column
,
column(width = 10,
offset = 0,
align = "center",
DT::dataTableOutput("DT1")
) #column
)#fluidrow
)
)
)
# Define server logic required to draw a histogram
server <- function(input, output,session) {
observeEvent(input$fetch_data_inputId, {
req(iris)
button_data <- colnames(iris)
merged_data <- reactive({
if( !is.null(cbind(iris[,1:4],iris3))) {
cbind(iris[,1:4],iris3)
} else {NULL}
})
}) #observeevent
output$DT1 <- renderDataTable({#
rendered_table <- merged_data()
DT::datatable(rendered_table)
})
}
# Run the application
shinyApp(ui = ui, server = server)
Minimum repr example - this works because the datatable is created within the ObserveEvent.
library(shiny)
library(shinyjs)
library(DT)
# Define UI for application that draws a histogram
ui <- fluidPage(
# Application title
titlePanel("testing 1 2 3"),
# Sidebar with a slider input for number of bins
sidebarLayout(
sidebarPanel(
),
# Show a plot of the generated distribution
mainPanel(
fluidRow(
column(width = 2,
offset = 0,
align = "center",
actionButton(inputId = "fetch_data_inputId",
label = "data")
) #column
,
column(width = 10,
offset = 0,
align = "center",
DT::dataTableOutput("DT1")
) #column
)#fluidrow
)
)
)
# Define server logic required to draw a histogram
server <- function(input, output,session) {
observeEvent(input$fetch_data_inputId, {
req(iris)
button_data <- colnames(iris)
merged_data <- reactive({
if( !is.null(cbind(iris[,1:4],iris3))) {
cbind(iris[,1:4],iris3)
} else {NULL}
})
output$DT1 <- renderDataTable({#
rendered_table <- merged_data()
DT::datatable(rendered_table)
})
}) #observeevent
}
# Run the application
shinyApp(ui = ui, server = server)
What I really need is for the reactive dataset to continue being created within observeEvent but to be accessible outside of the ObserveEvent environment so that i use it in other parts of the app, but I suspect it's the wrong approach. So anything that works would be great.
library(shiny)
library(shinyjs)
library(DT)
# Define UI for application that draws a histogram
ui <- fluidPage(
# Application title
titlePanel("testing 1 2 3"),
# Sidebar with a slider input for number of bins
sidebarLayout(
sidebarPanel(
),
# Show a plot of the generated distribution
mainPanel(
fluidRow(
column(width = 2,
offset = 0,
align = "center",
actionButton(inputId = "fetch_data_inputId",
label = "data")
) #column
,
column(width = 10,
offset = 0,
align = "center",
DT::dataTableOutput("DT1")
) #column
)#fluidrow
)
)
)
# Define server logic required to draw a histogram
server <- function(input, output,session) {
merged_data <- eventReactive(input$fetch_data_inputId, {
req(iris)
button_data <- colnames(iris)
if( !is.null(cbind(iris[,1:4],iris3))) {
cbind(iris[,1:4],iris3)
} else {NULL}
}) #eventReactive
output$DT1 <- renderDataTable({#
rendered_table <- merged_data()
DT::datatable(rendered_table)
})
}
# Run the application
shinyApp(ui = ui, server = server)
I want to create a button that generates a random number and save all random numbers on my server that I can evaluate that data later.
Unfortunately I am not able to generate a vector with all random numbers. Somehow a for loop is not working. Thanks!
library(shiny)
ui <- fluidPage(
actionButton("button", "Show")
)
server <- function(input,output) {
eventReactive(input$button, {
counter <- sample(1:10,1)
})
}
shinyApp(server = server, ui = ui)
You don't need a for loop in R to generate a vector of random numbers, there are many functions for random number generation, please check here for some examples.
Here is a sample code:
library(shiny)
ui <- shinyUI(fluidPage(
titlePanel("Random number generator"),
sidebarLayout(
sidebarPanel(
sliderInput("rangeSl", "Range", min = 0,
max = 100, value = c(40, 60)
),
numericInput("num", "Quantity:", 20, min = 1, max = 100, width = "40%"),
actionButton("generateBt", "Generate Numbers")
),
mainPanel(
verbatimTextOutput("result")
)
)
))
server <- shinyServer(function(input, output) {
output$result <- renderPrint({
if (input$generateBt > 0 )
isolate(
floor(runif(input$num, min = input$rangeSl[1], max = input$rangeSl[2]))
)
})
})
shinyApp(ui = ui, server = server)
I want to create a vector by using observe() in R shiny. In the code blow, how can I create a vactor where all the input$n are concatenated. At the present time, I can only display a single value but could not concatenate and display all the inputs from the sliderInput.
ui.R
library(shiny)
fluidPage(
titlePanel("Observer demo"),
fluidRow(
column(4, wellPanel(
sliderInput("n", "N:",
min = 10, max = 1000, value = 200, step = 10)
)),
column(8,
tableOutput("text")
)
)
)
server.R
library(shiny)
function(input, output, session) {
observed=reactiveValues(
input=NULL
)
observe({
observed$input=input$n
# observed$input=c(observed$input,input$n) # tried this but not working
})
output$text <- renderTable({
observed$input
})
}
If you add print(observed$input) in your observer, you will see that when you use observed$input=c(observed$input,input$n) you run into an infinite loop as the observe is reactive to observe$input and will run again as soon as you modify it.
To prevent this, you can use isolate:
observed$input=c(isolate(observed$input),input$n)
As in #Pork Chop 's answer, you can also use observeEvent to only observe input$n.
Try this, you can use cbind or rbind depending on your needs
rm(list = ls())
library(shiny)
ui <- fluidPage(
titlePanel("Observer demo"),
fluidRow(
column(4, wellPanel(
sliderInput("n", "N:",
min = 10, max = 1000, value = 200, step = 10)
)),
column(8,
tableOutput("text")
)
)
)
server <- function(input, output, session) {
observed=reactiveValues(
input=NULL
)
observeEvent(input$n,{
observed$input <- cbind(observed$input,input$n)
})
output$text <- renderTable({
print(observed$input)
observed$input
})
}
shinyApp(ui <- ui, server <- server)