update value in a column of a table based on input in shiny - shiny-reactivity

Question

I am new in Shiny and I need yours knowledge. I will try explain with detail:
In my application, the user upload a csv file. This information is visualized in 2 tabPanel. In the first tabPanel named Original, the user can see the original dataset. The other one named Procesado, the user can see a select input with values from 1 to 4 and only 2 columns (internally before to show the information, the dataset is edited, eliminating columns and rows).
I want update the values of the first column every time that the user change the value in the select input. I tried with renderUI and reactive, but is not working. Thanks
shinyUI(
pageWithSidebar(
headerPanel("Ciclismo - Calidad de la sesion"),
sidebarPanel(
p("Escoge el dataset generado por la aplicacion de ciclismo Polar"),
fileInput("file1","Escoge un archivo CSV",
multiple = FALSE,
accept = c(".csv")),
tags$hr(),
submitButton("Evaluar Dataset")
),
mainPanel(
tabsetPanel(
tabPanel("Original", tableOutput("contents")),
tabPanel("Procesado",
p("Selecciona la zona de entrenamiento a evaluar"),
selectInput("zone", "Zona de entrenamiento",
choices = c("1", "2", "3", "4")),
uiOutput("ui"),
tags$hr(),
tableOutput("modified"),),
tabPanel("Graficos",
h3(textOutput("output_text")),
plotOutput("output_plot")
)
)
)
)
)
The code on the server is
shinyServer(function(input, output) {
output$contents <- renderTable({
#data.frame(x=auto)
req(input$file1)
# when reading semicolon separated files,
# having a comma separator causes `read.csv` to error
#tryCatch(
#{
df <- read.csv(input$file1$datapath)
#},
#error = function(e) {
# return a safeError if a parsing error occurs
# stop(safeError(e))
# }
#)
return(df)
})
output$ui <- renderUI({
switch(input$zone,
"1" = cbind(ZONA = 1, dfProc),
"2" = cbind(ZONA = 2, dfProc),
"3" = cbind(ZONA = 3, dfProc),
"4" = cbind(ZONA = 4, dfProc))
})
output$modified <- renderTable({
req(input$file1)
dff <- read.csv(input$file1$datapath)
#return(df)
dfN = dff[-c(1,2,3),-c(1,2)]
FC = dfN[,-c(2:26)]
#Se convierte en dataframe para realizar operaciones
dfProc = data.frame(FC)
newdata_test = cbind(ZONA = 1,dfProc)
return(newdata_test)
})
})

Answer 1

Finally, I did it.
I put two eventReactive. The first one is to read the CSV file. The second one with the input Zona using cbind function for insert the input value in the column. I hope this answer can help to other people
df <- eventReactive(input$csv,{
req(input$csv)
dff <- read.csv(input$csv$datapath)
#The dataset is updated, eliminating rows and columns
dfN = dff[-c(1,2,3),-c(1,2)]
FC = dfN[,-c(2:26)]
dfProc = data.frame(FC)
return(dfProc)
})
datos <- eventReactive(input$zone,{
newtable = cbind(input$zone, df())
})
output$modified <- renderTable({datos()})