Gnuplot groups several bars

Question

I use gnuplot to create graphs for several tests.
For each test, I have many configurations to build. I want to plot the graph (my y axis) versus the reference (x axis). For each test, there will be several columns that differ in their color.

I generated the same type of graphs some time ago using some python script, but I don't know how to do this in gnuplot.

Answer 1

This is the source data languages.data :

 Title C C++ Java Python "Writing code" 6 4 10 1 "Understanding code" 6 3 4 1 "Generating prime numbers" 3 1 2 10 

With this code:

 set title "Benchmarks" C = "#99ffff"; Cpp = "#4671d5"; Java = "#ff0000"; Python = "#f36e00" set auto x set yrange [0:10] set style data histogram set style histogram cluster gap 1 set style fill solid border -1 set boxwidth 0.9 set xtic scale 0 # 2, 3, 4, 5 are the indexes of the columns; 'fc' stands for 'fillcolor' plot 'languages.data' using 2:xtic(1) ti col fc rgb C, '' u 3 ti col fc rgb Cpp, '' u 4 ti col fc rgb Java, '' u 5 ti col fc rgb Python 

Provides the following histogram:

But I would suggest using R , whose syntax is more readable:

 library(ggplot2) # header = TRUE ignores the first line, check.names = FALSE allows '+' in 'C++' benchmark <- read.table("../Desktop/gnuplot/histogram.dat", header = TRUE, row.names = "Title", check.names = FALSE) # 't()' is matrix tranposition, 'beside = TRUE' separates the benchmarks, 'heat' provides nice colors barplot(t(as.matrix(benchmark)), beside = TRUE, col = heat.colors(4)) # 'cex' stands for 'character expansion', 'bty' for 'box type' (we don't want borders) legend("topleft", names(benchmark), cex = 0.9, bty = "n", fill = heat.colors(4)) 

In addition, it provides a slightly more beautiful conclusion: