CODEWITHSUNDEEP
rsortingshiny
Tomas H
Tomas H

Reputation: 713

Sorting dataframe by two columns when one is selected by user

I want to sort data frame by two columns first is factor and second numeric but this is selected in shiny.

When I use this line with specified columns it works well.

 iris1<-iris[with(iris,order(Species,Sepal.Length,decreasing = T)), ]

But inside shiny I replace Sepal.Length with reactive values and this returns error. Please see MRE

# ui.R
library(shiny)


shinyUI(pageWithSidebar(

  # Application title
  headerPanel("Miles Per Gallon"),

  sidebarPanel(selectInput("a","select column",c("Sepal.Length","Sepal.Width"))),

  mainPanel(tableOutput("b"))
))

# server.R   
library(shiny)


shinyServer(function(input, output) {

  col<-reactive({input$a})
 output$b<- renderTable({
########### this line probably causes the problem
   iris1<-iris[with(iris,order(Species,col(),decreasing = T)), ]
})
})

Error I get is

Error in order(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,  : 
  argument lengths differ

Upvotes: 1

Views: 279

Answers (1)

zx8754
zx8754

Reputation: 56219

Try this, using get() to convert string to column name:

col <- "Sepal.Width"
iris[with(iris, order(Species, get(col), decreasing = TRUE)), ]

And within shiny it should be: get(col()).

Note that input$a is already reactive, so we can say: get(input$a)

Upvotes: 3

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