How to generate a number of most distinctive colors in R?

Question

I joined all qualitative palettes from RColorBrewer package. Qualitative palettes are supposed to provide X most distinctive colours each. Of course, mixing them joins into one palette also similar colours, but that's the best I can get (74 colors).

library(RColorBrewer)
n <- 60
qual_col_pals = brewer.pal.info[brewer.pal.info$category == 'qual',]
col_vector = unlist(mapply(brewer.pal, qual_col_pals$maxcolors, rownames(qual_col_pals)))
pie(rep(1,n), col=sample(col_vector, n))

Other solution is: take all R colors from graphical devices and sample from them. I removed shades of grey as they are too similar. This gives 433 colors

color = grDevices::colors()[grep('gr(a|e)y', grDevices::colors(), invert = T)]

pie(rep(1,n), col=sample(color, n))

with 200 colors n = 200:

pie(rep(1,n), col=sample(color, n))

Here are a few options:

1. Have a look at the palette function:

    palette(rainbow(6))     # six color rainbow
    (palette(gray(seq(0,.9,len = 25)))) #grey scale
   

2. And the colorRampPalette function:

    ##Move from blue to red in four colours
    colorRampPalette(c("blue", "red"))( 4) 
   

3. Look at the RColorBrewer package (and website). If you want diverging colours, then select diverging on the site. For example,

    library(RColorBrewer)
    brewer.pal(7, "BrBG")
   

4. The I want hue web site gives lots of nice palettes. Again, just select the palette that you need. For example, you can get the rgb colours from the site and make your own palette:

    palette(c(rgb(170,93,152, maxColorValue=255),
        rgb(103,143,57, maxColorValue=255),
        rgb(196,95,46, maxColorValue=255),
        rgb(79,134,165, maxColorValue=255),
        rgb(205,71,103, maxColorValue=255),
        rgb(203,77,202, maxColorValue=255),
        rgb(115,113,206, maxColorValue=255)))
   

You can also try the randomcoloR package:

library(randomcoloR)
n <- 20
palette <- distinctColorPalette(n)

You can see that a set of highly distinct colors are chosen when visualizing in a pie chart (as suggested by other answers here):

pie(rep(1, n), col=palette)

Shown in a pie chart with 50 colors:

n <- 50
palette <- distinctColorPalette(n)
pie(rep(1, n), col=palette)

Not an answer to OP's question but it's worth mentioning that there is the viridis package which has good color palettes for sequential data. They are perceptually uniform, colorblind safe and printer-friendly.

To get the palette, simply install the package and use the function viridis_pal(). There are four options "A", "B", "C" and "D" to choose

install.packages("viridis")
library(viridis)
viridis_pal(option = "D")(n)  # n = number of colors seeked

There is also an excellent talk explaining the complexity of good colormaps on YouTube:

A Better Default Colormap for Matplotlib | SciPy 2015 | Nathaniel Smith and Stéfan van der Walt