Multiple line graphs using plotly in shiny R

Question

I'm new to shiny R and Plotly. I'm trying to build a dashboard that has two drop-down boxes and we take input through these dropdown boxes and plot Plotly graphs. All the datasets have time, temp, and weight columns. time goes on the x-axis and for y-axis we can select either temp or weight or maybe both.

1. the first drop-down takes the input to which dataset to select.

2. second dropdown box takes the input to select the variable from the dataset selected. Most of the things I have figured out, however, y-axis label does not change dynamically. the label is getting (input$variable) instead of temp or weight.

here is the shiny r output also here is the reproducible example and my code

library(shiny)
library(plotly)
library(DT)

df1 <- data.frame("time" = 1:10, "temp" = c(21,15,31,12,23,45,67,34,54,10), "weight" = c(10,20,30,40,65,35,68,89,100,23), stringsAsFactors = FALSE)
df2 <- data.frame("time" = 1:10, "temp" = c(31,65,31,22,23,45,67,54,54,45), "weight" = c(30,20,40,40,65,85,68,89,14,24), stringsAsFactors = FALSE)





    ui <- fluidPage(

            titlePanel( div(column(width = 5, h2('title here')), )),
            # Input: Selector for choosing dataset
            selectInput(inputId = "dataset",
                        label = "Choose a dataset:",
                        choices = c("df1","df2")),

            selectInput(inputId = "variable",
                        label = "Variable selection", 
                        choices = c("temp","weight"),
                        selected = "weight",
                        multiple = FALSE),
            mainPanel(
                    # Output
                    tabsetPanel(type = "tabs",
                                tabPanel("Plot", plotlyOutput('plot')),
                                tabPanel("Data", DT::dataTableOutput("table")),
                                tabPanel("Key_metrics", DT::dataTableOutput("Key_metrics")))
            )
    )

    server <- function(input, output) {
            dataDf <- reactive({
                    temp <- get(input$dataset)

            })

            output$plot <- renderPlotly(
                    plot_ly(dataDf(), x = ~time, y =~get(input$variable), type = 'scatter', mode = 'lines', name = "temp") %>%
                            add_trace(dataDf(), x = ~time, y = ~weight, type = 'scatter', mode = 'lines',name = "weight") 

            )

            output$table <- DT::renderDataTable({
                    dataDf()
            })
            output$Key_metrics <- DT::renderDataTable({

            })

    }

    shinyApp(ui,server)

Answer 1

You can specify axis labels in layout(). Note that xaxis and yaxis require a list as argument (see here for more details):

output$plot <- renderPlotly(
    plot_ly(dataDf(), x = ~time, y =~get(input$variable), type = 'scatter', mode = 'lines', name = "temp") %>%
      add_trace(dataDf(), x = ~time, y = ~weight, type = 'scatter', mode = 'lines',name = "weight") %>%
      layout(xaxis = list(title = "Time"), yaxis = list(title = input$variable))

)

Edit: following a comment, here's how to plot two lines if two variables are selected and one otherwise (don't forget to put multiple = TRUE in selectInput():

library(shiny)
library(plotly)
library(DT)

df1 <- data.frame("time" = 1:10, "temp" = c(21,15,31,12,23,45,67,34,54,10), "weight" = c(10,20,30,40,65,35,68,89,100,23), stringsAsFactors = FALSE)
df2 <- data.frame("time" = 1:10, "temp" = c(31,65,31,22,23,45,67,54,54,45), "weight" = c(30,20,40,40,65,85,68,89,14,24), stringsAsFactors = FALSE)



ui <- fluidPage(

  titlePanel( div(column(width = 5, h2('title here')), )),
  # Input: Selector for choosing dataset
  selectInput(inputId = "dataset",
              label = "Choose a dataset:",
              choices = c("df1","df2")),

  selectInput(inputId = "variable",
              label = "Variable selection", 
              choices = c("temp","weight"),
              selected = "weight",
              multiple = TRUE),
  mainPanel(
    # Output
    tabsetPanel(type = "tabs",
                tabPanel("Plot", plotlyOutput('plot')),
                tabPanel("Data", DT::dataTableOutput("table")),
                tabPanel("Key_metrics", DT::dataTableOutput("Key_metrics")))
  )
)

server <- function(input, output) {
  dataDf <- reactive({
    temp <- get(input$dataset)

  })

  output$plot <- renderPlotly({

    if (length(input$variable) > 1){
      plot_ly(dataDf(), x = ~time, y =~get(input$variable[1]), 
              type = 'scatter', mode = 'lines', name = "temp") %>%
        add_trace(dataDf(), x = ~time, y = ~get(input$variable[2]), 
                  type = 'scatter', mode = 'lines',name = "weight") %>%
        layout(xaxis = list(title = "Time"))
    }
    else {
      plot_ly(dataDf(), x = ~time, y =~get(input$variable[1]), type = 'scatter', mode = 'lines', name = "temp") %>%
        add_trace(dataDf(), x = ~time, y = ~get(input$variable[1]), type = 'scatter', mode = 'lines',name = "weight") %>%
        layout(xaxis = list(title = "Time"), yaxis = list(title = input$variable))
    }

  })

  output$table <- DT::renderDataTable({
    dataDf()
  })
  output$Key_metrics <- DT::renderDataTable({

  })

}

shinyApp(ui,server)

Put what you want as y-axis label based on the original answer. Note that this answer only works if there are two choices.