I am new with Shiny App and I wanted to try something very simple but I'm having a hard time with it.

I have a data that looks like this:

  Proyecto <- c("ECO","ECO", "ECO", "ECO", "FECHIC", "FECHIC")
  Encuesta <- c(1, 2, 1,1, 1, 1)
  Visita <- c(1,2,3, 1, 1, 1)
  acep <- (1,1,1,1,1,1)
  covid_date <- c("2020-06-20", "2020-12-21", "2021-05-02", "2020-06-22", "2020-06-20", "2020-12-21")
  covid_fechic <- c(2,1,2,2,2,NA)
  BASE_COMPLETA <- tibble(Proyecto, Encuesta, Visita, acep, covid_date, covid_fechic)

I want to create an App that could have as an Input:

1. Proyecto (selectInput)
2. Encuesta (selectInput)
3. Visita (selectInput)
4. Any variable from the dataset, such as covid_date or covid_fechic (textInput)

With these input I would like to create a table that first, filter by Proyecto, Encuesta and Visita, and later select only the Variable that I chose, arrange it, group it and summarise in a way that could show me the different options of the variable and how many people choose any of those options.

Without the Shiny App is something like this:

    BASE_COMPLETA %>%
      filter(Proyecto == "FECHIC") %>%
      filter(Encuesta == 1) %>%
      filter(Visita == 1) %>% 
      filter(acep == 1) %>% 
      select(covid_fechic) %>%
      arrange(covid_fechic) %>% 
      group_by(covid_fechic) %>% 
      summarise(n = n()) %>% 
      print()

But when I try this in my Shiny App, it seems like is only working until the select part, I can't get the arrange, group_by or summarise.

Is it because I can't use the same input variable many times?

Here is my very simple Shiny Code:

lista_proyecto <- c("FECHIC", "ECO")
lista_encuestas <- c(1, 2)
lista_visitas <- c(1, 2, 3)


ui <- fluidPage(
  
  theme = shinytheme("flatly"),
  
  h1(id="big-heading", "Encuesta COVID"),
  tags$style(HTML("#big-heading{color: #092F87;}")),
  
  sidebarLayout(
    sidebarPanel(
      width = 12,
      selectInput("Proyecto",
                  label = h4("Proyecto:"),
                  choices = lista_proyecto),
      selectInput("Encuesta",
                  label = h4("Encuesta:"),
                  choices = lista_encuestas),
      selectInput("Visita",
                  label = h4("Ronda:"),
                  choices = lista_visitas),
      textInput("Variable", 
                label = h4("Variable de interés"),
                value = "covid_date")
    ),
    mainPanel(
      fluidRow(DTOutput("Tabla3"))
    )
  )
)

server <- function(input, output) {
  
  output$Tabla3 <- renderDT({
    BASE_COMPLETA %>%
      filter(Proyecto == input$Proyecto) %>%
      filter(Encuesta == input$Encuesta) %>% 
      filter(Visita == input$Visita) %>% 
      filter(acep == 1) %>% 
      select(input$Variable) %>%
      arrange(input$Variable) %>% 
      group_by(input$Variable) %>% 
      summarise(n = n()) %>% 
      print()
    
  }, options = list(bFilter=0))
  
  
}

shinyApp(ui = ui, server = server)

Can anybody help me to undestand where is the problem and what can I do to make this works? Thanks in advance!.

CodePudding user response：

knowing that the value from the inputs are characters, we can use the special construct .data[[]] to select a variable using a string.

  output$Tabla3 <- renderDT({
    BASE_COMPLETA %>%
      filter(Proyecto == input$Proyecto) %>%
      filter(Encuesta == input$Encuesta) %>% 
      filter(Visita == input$Visita) %>% 
      filter(acep == 1) %>% 
      select(.data[[input$Variable]]) %>%
      arrange(.data[[input$Variable]]) %>% 
      group_by(.data[[input$Variable]]) %>% 
      summarise(n = n()) %>% 
      print()
    
  }, options = list(bFilter=0))

alternatively we could also used function get().

For more information see Programming with dplyr.

app code:

library(shiny)
library(DT)
library(shinythemes)

Proyecto <- c("ECO", "ECO", "ECO", "ECO", "FECHIC", "FECHIC")
Encuesta <- c(1, 2, 1, 1, 1, 1)
Visita <- c(1, 2, 3, 1, 1, 1)
acep <- c(1, 1, 1, 1, 1, 1)
covid_date <- c("2020-06-20", "2020-12-21", "2021-05-02", "2020-06-22", "2020-06-20", "2020-12-21")
covid_fechic <- c(2, 1, 2, 2, 2, NA)
BASE_COMPLETA <- tibble(Proyecto, Encuesta, Visita, acep, covid_date, covid_fechic)

lista_proyecto <- c("FECHIC", "ECO")
lista_encuestas <- c(1, 2)
lista_visitas <- c(1, 2, 3)


ui <- fluidPage(
  theme = shinytheme("flatly"),
  h1(id = "big-heading", "Encuesta COVID"),
  tags$style(HTML("#big-heading{color: #092F87;}")),
  sidebarLayout(
    sidebarPanel(
      width = 12,
      selectInput("Proyecto",
        label = h4("Proyecto:"),
        choices = lista_proyecto
      ),
      selectInput("Encuesta",
        label = h4("Encuesta:"),
        choices = lista_encuestas
      ),
      selectInput("Visita",
        label = h4("Ronda:"),
        choices = lista_visitas
      ),
      textInput("Variable",
        label = h4("Variable de interés"),
        value = "covid_date"
      )
    ),
    mainPanel(
      fluidRow(DTOutput("Tabla3"))
    )
  )
)

server <- function(input, output) {
  output$Tabla3 <- renderDT(
    {
      BASE_COMPLETA %>%
        filter(Proyecto == input$Proyecto) %>%
        filter(Encuesta == input$Encuesta) %>%
        filter(Visita == input$Visita) %>%
        filter(acep == 1) %>%
        select(.data[[input$Variable]]) %>%
        arrange(.data[[input$Variable]]) %>%
        group_by(.data[[input$Variable]]) %>%
        summarise(n = n()) %>%
        print()
    },
    options = list(bFilter = 0)
  )
}

shinyApp(ui = ui, server = server)