Change plotly chart y variable based on selectInput

Question

I'm creating a simple line chart which renders correctly in Shiny.

I've now added a selectInput with the names of 2 different measures, written as they appear in my data set. I'd like my y variable to change accordingly.

p <- plot_ly(data = LineChartData(), x= Calendar.Month, y = input$Measure, type = "line", group = Calendar.Year, col = Calendar.Year)

Unfortunately, the chart renders with just one point. It's not taking input$Measure and finding that field in my data set.

I know when using ggplot, i'd switch my aes to aes_string. Is there a similar solution in plotly?

EDIT: here's some reproducible code

Here's the ui.R file

    #ui.R

shinyUI(
  fluidPage(
    titlePanel("Inbound Intermediary Performance"),

  sidebarLayout(
    sidebarPanel(
    h4("Parameters"),
    br(),
    selectInput("Measure", "Measure", c("Var1","Var2"))
    ),
    mainPanel(

      plotlyOutput("lineChart")

      )

  )

        )

)

server.R

#server.R
library(plotly)
library(shiny)
library(ggplot2)





#Create data
data <- data.frame(Month = c(1,2,3,4,5,6,7,8,9,10,11,12), Var1 = c(36,33,30,27,24,21,18,15,12,9,6,3), Var2 = c(4,8,12,16,20,24,28,32,36,40,44,48))



shinyServer(function(input, output) {


  #Create plot

  output$lineChart <- renderPlotly({

    #using ggplot
    p <- ggplot(data=data, aes_string(x='Month', y = input$Measure)) +geom_line(size = 1.5) + theme_minimal()
    ggplotly(p)



    #Using PLotly
    #p <- plot_ly(data = data, x= Month, y = input$Measure, type = "line")

  })

})

In the example above, I can use my drop down to switch between Var1 and Var2. My plot changes accordingly. The code uses ggplot and it's aes_string function to take an input. This is then converted into a plotly interactive plot using the ggplotly function.

Is there a way I can do this natively with plotly?

Answer 1

Use base::get() function:

p <- plot_ly(data = data, x = ~Month, y = ~get(input$Measure), type = "line")

or the same using ggplot:

p <- ggplot(data = data, aes(x = Month, y = get(input$Measure))) +
geom_line(size = 1.5) + 
theme_minimal()
ggplotly(p)