Plotly - Create Pie Chart with continuous color scale

Question

I'm looking to create a plotly chart where the colors of each slice another variable in the dataframe. This is pretty simple to do in ggplot2, however, I'm struggling to convert this to plotly.

My sample code is here:

Product <- c("Product1","Product2","Product3","Product4","Product5","Product6","Product7")
Value <- c(1000000,200002,599996,1399994,2199992,2999990,3799988)
Rating = c(0.24, 0.28, 0.17, 0.1, 0.5, 0.6, 0.34)
df <- data.frame(Product,Value, Rating)

plot_ly(df, labels = ~Product, values = ~Value, type = 'pie', textinfo = 'label+percent',
         marker = list(color = ~Rating)) %>%
layout(xaxis = list(showgrid = FALSE, zeroline = FALSE, showticklabels = FALSE),
     yaxis = list(showgrid = FALSE, zeroline = FALSE, showticklabels = FALSE))

And this is the output:

It seems like I am not doing something right with the "color" attribute. I would like for there to be a continuous scale color scheme, preferably a red color when the Rating variable is near 0 and green when it is near 1.

Thanks.

Answer 1

You could

• sort your dataframe

  sorted_df <- df[order(df$Rating),]
  

• add custom colors using colorRampPalette

  gradient <- colorRampPalette(c('red', 'green'))
  sorted_df$colors <- gradient(dim(df)[1])[as.numeric(cut(sorted_df$Rating,
                                                          breaks = dim(df)[1]))]
  

• assign the colors to your plot

  marker = list(colors = ~colors)
  

which gives you

The color scale could use some tweaking.

---

Product <- c("Product1","Product2","Product3","Product4","Product5","Product6","Product7")
Value <- c(1000000,200002,599996,1399994,2199992,2999990,3799988)
Rating = c(0.24, 0.28, 0.17, 0.1, 0.5, 0.6, 0.34)
df <- data.frame(Product,Value, Rating)
sorted_df <- df[order(df$Rating),]
gradient <- colorRampPalette(c('red', 'green'))

sorted_df$colors <- gradient(dim(df)[1])[as.numeric(cut(sorted_df$Rating,
                                                        breaks = dim(df)[1]))]


plot_ly(sorted_df, labels = ~Product, values = ~Value, type = 'pie', textinfo = 'label+percent',
        marker = list(colors = ~colors)) %>%
  layout(xaxis = list(showgrid = FALSE, zeroline = FALSE, showticklabels = FALSE),
         yaxis = list(showgrid = FALSE, zeroline = FALSE, showticklabels = FALSE))