How to efficiently alias column variables in the selectInput function in R Shiny

Question

Edited for clarity:

I'm building an app in shiny to explore data in a scatterplot. The simplified code is below:

library(shiny)
library(ggplot2)
library(DT)
library(tools)
library(dplyr)
library(tidyverse)

#load data
Data <- Electorate_Data

# Define UI for application 
ui <- fluidPage(
titlePanel("Scatterplot"),

br(),

# Sidebar layout with a input and output definitions
sidebarLayout(
# Inputs
sidebarPanel(
  # Select variable for y-axis
  selectInput(inputId = "y", label = "Y-axis:",
              choices = colnames(Data[6:32])
  ),
  # Select variable for x-axis
  selectInput(inputId = "x", label = "X-axis:",
              choices = colnames(Data[6:32])
  ),

  width = 6
),

# Output:
mainPanel(
   # Create a container for tab panels
      tabsetPanel(

    tabPanel(
      title = "Explore the Data",
      # Show scatterplot
      plotOutput(outputId = "scatterplot")
     )

  ),

  width = 6  
)
 )
)

# Define server function required to create the scatterplot
server <- function(input, output) {

  # Create scatterplot object the plotOutput function is expecting
  output$scatterplot <- renderPlot({
    ggplot(data = Data, aes_string(x = input$x, y = input$y)) +
      geom_point() 
  })

}

# Create a Shiny app object
shinyApp(ui = ui, server = server)

My issue is, when I select the column names (using the function colnames) to be the choices in the selectInput function, and the colnames contain spaces (i.e. "Year 12" instead of Year12), my scatterplot doesn't work, giving the error message:

Error: :1:6: unexpected 'in' 1: Born in

Code Example

# Select variable for y-axis
  selectInput(inputId = "y", label = "Y-axis:",
              choices = colnames(Data[6:32])

Now, if I alias each variable, for example using the following code, the app works perfectly fine:

# Select variable for y-axis
  selectInput(inputId = "y", label = "Y-axis:",
          choices = "Year12" = "Year 12", 
                    "Born_Aus" = "Born in Australia",
                    "NoSchool" = "% of the Population Above 15 Years of Age that Didn't Attend School")
  ),

My question is - is there a way to alias the names more efficiently in such a way that I can automate the aliasing process. I've tried a few hack approaches using the names() function, but so far it has only thrown up errors.

At the end of the day I can solve this manually, but surely there is a better way.

Thanks

Edit:

I've included a subset of the data if that helps. You would have to change the code of:

  # Select variable for x-axis
  selectInput(inputId = "x", label = "X-axis:",
              choices = colnames(Data[6:32])
  ),

to just

choices = colnames(Data)

for both the X and Y selectInputs

Data:

> head(Electorate_Data[14:18])
  Born in Australia       LOTE    NoSchool    Year12 Median_age
1         0.6126271 0.29805068 0.012132744 0.5481394         36
2         0.6419959 0.27278743 0.006160949 0.4610346         39
3         0.8234175 0.05199925 0.002323880 0.3564276         40
4         0.5633673 0.45200442 0.011578501 0.4933828         38
5         0.8186847 0.06066808 0.005270832 0.2701636         44
6         0.4439803 0.59099798 0.017304021 0.5374834         35

Answer 1

In general, lets assume you have a vector of names that should be returned by the selectInput() called x. And you have a second, equally long vector, of names that you what the user to see when making the selection, called y. You can do what you want by first giving x the names of y like so:

names(x)<-y 

Then you can use x in the choices= argument to selectInput(). The user will see the names from y as the choices, but the selectInput() will return the values from x.

Answer 2

I don't know why your shiny does not support the columns names containing spaces. The code below works fine on my machine. Provide a reproducible example is always helpful for others to help you.

library(shiny)
df <- iris[,-5]
colnames(df) <- sub('\\.', ' ', colnames(df))
ui <- fluidPage(
  titlePanel("Scatterplot and Regression Calculator"),

  br(),

  # Sidebar layout with a input and output definitions
  sidebarLayout(
    # Inputs
    sidebarPanel(
      # Select variable for y-axis
      selectInput(inputId = "y", label = "Y-axis:",
                  choices = colnames(df)
      )
    ),
    mainPanel(
      plotOutput(outputId = "plot")
    )
  )
)
server <-function(input, output) {
  output$plot <- renderPlot({
    hist(df[[input$y]])
  })
}
shinyApp(ui = ui, server = server)