Colorbar in legend when using plotly

问题

Here is my data:

set.seed(42)
mydata = data.frame(A = rnorm(20), B = rnorm(20), Index = sample(190:400,20))    

I am trying to divide the data into 20 different intervals based on the Index value and then color the scatter points according to their interval value. Below is my code. It is not working perfectly.

cols = colorRampPalette(c("red", "black"), space = "rgb")(20)
mydata$interval = cut(mydata$Index,breaks = 20)
mydata$cols = cols[mydata$interval]
require(plotly)
x = list(title = "A")
y = list(title = "B")
plot_ly(mydata, x = ~A, y = ~B,  color = ~cols, type = "scatter",
                        mode = 'markers', hoverinfo = 'text',
                        text = ~paste(interval)) %>%
                        layout(xaxis = x, yaxis = y)

How do I get a colorbar in the legend where the colors are based on Index value.

回答1:

Are you looking for this:

plot_ly(mydata, x = ~A, y = ~B, type = "scatter",
        mode = 'markers', hoverinfo = 'text', colors = colorRampPalette(c("red", "black"), space = "rgb")(20), color = ~Index, text = ~paste(interval), marker = list(size=14)) %>%
        layout(xaxis = x, yaxis = y) %>%
        colorbar(title = "My Legend")

来源：https://stackoverflow.com/questions/41797368/colorbar-in-legend-when-using-plotly