How do I split grouped bar chart in R by variable

Question

I am trying to split the attached grouped bar chart by the variable spec . Two thoughts on best way to do this are by adding facet_grid() or if a filter can be applied to the static output? Can either be done? Any advice appreciated.

a sample is below:

period <- c('201901', '201901', '201904', '201905')
spec <- c('alpha', 'bravo','bravo', 'charlie')
c <-  c(5,6,3,8)
e <- c(1,2,4,5)


df <- data.frame(period, spec, c,e)

library(tidyverse)
library(plotly)

plot_ly(df, x =~period, y = ~c, type = 'bar', name = "C 1", marker = list(color = 'lightsteelblue3')) 
%>%
  add_trace(y = ~e, name = "E 1", marker = list(color = 'Gray')) %>%
  layout(xaxis = list(title="", tickangle = -45),
         yaxis = list(title=""),
         margin= list(b=100), 
         barmode = 'group'
  )

Answer 1

I am not sure if you are plotting what you actually want to achieve? My suggestion is to create your plot using standard ggplot and then use ggplotly .

For this, you also need to reshape your data and make it a bit longer.

library(tidyverse)
library(plotly)

period <- c('201901', '201901', '201904', '201905')
spec <- c('alpha', 'bravo','bravo', 'charlie')
c <-  c(5,6,3,8)
e <- c(1,2,4,5)


df <- data.frame(period, spec, c,e) %>% 
        pivot_longer(cols = c(c,e), names_to = 'var', values_to = 'val')


p <- ggplot(df, aes(period, val, fill = var)) +
  geom_col(position = position_dodge()) +
  facet_grid(~spec)

ggplotly(p)

Answer 2

It's probably easier to use facets here, but a more "interactive" option would be to use a filter transforms which gives you a drop-down menu in the top left corner of your plot.

spec.val <- unique(df$spec)
plot_ly(
    df %>% pivot_longer(-c(period, spec)),
    x = ~period, y = ~value, color = ~name,
    type = "bar",
    transforms = list(
        list(
            type = "filter",
            target = ~spec,
            operation = "=",
            value = spec.val[1]))) %>%
    layout(
        updatemenus = list(
            list(
                type = "drowdown",
                active = 0,
                buttons = map(spec.val, ~list(
                    method = "restyle",
                    args = list("transforms[0].value", .x),
                label = .x)))))