How to make plotly work with shiny and gridExtra? - r

Question

I'm using R shiny would like to put several ggplotly plots side by side with the help of gridExtra.
One plot (without gridExtra) works just fine:
library(shiny)
library(plotly)
u <- fluidPage(plotlyOutput(outputId = "myplots"))
s <- function(input, output) {
pt1 <- reactive({
ggplotly(qplot(42))
})
output$myplots <- renderPlotly({
pt1()
})
}
shinyApp(u, s)
Now when I try to add one more plot via gridExtra, it refused to work:
library(shiny)
library(plotly)
library(gridExtra)
u <- fluidPage(plotlyOutput(
outputId = "myplots"
))
s <- function(input, output){
pt1 <- reactive({
ggplotly(qplot(42))
})
pt2 <- reactive({
ggplotly(qplot(57))
})
output$myplots <- renderPlotly({
grid.arrange(pt1(), pt2(),
widths = c(1, 1),
ncol = 2)
})
}
shinyApp(u, s)
giving me
Error in gList: only 'grobs' allowed in "gList"

Answer 1

Rather than using grid.arrange to pass many plots to a single plotlyOutput, it would be better to set up your ui to accept several plots and then pass them individually. For example, your ui and server could look like this
Note that defining columns like this uses Bootstrap theming, which means the widths need to add to 12. Thats why I've defined each column to have a width of 6 - each will naturally fill half the page
library(shiny)
library(plotly)
library(gridExtra)
u <- fluidPage(
fluidRow(
column(6,
plotlyOutput("pt1")),
column(6,
plotlyOutput("pt2"))
)
)
s <- function(input, output){
output$pt1 <- renderPlotly({
ggplotly(qplot(42))
})
output$pt2 <- renderPlotly({
ggplotly(qplot(57))
})
}
shinyApp(u, s)