# Beautiful boxplots in pgfplots

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Recently, I wanted to create boxplots from a data file for a paper I was writing using pgfplots. Turns out that’s more difficult than expected, especially since the (otherwise very useful) documentation is a bit meager in this point.

Some “features” of this plot that took me a while to set up correctly:

• Box design with fill color and black border
• Nice color scheme (based on ColorBrewer)
• Clean plot without any unnecessary clutter
• Getting pgfplots to work with data in row format (instead of column format, as expected by the boxplot function)

This is the code I used to generate the figure (link to code file:

\documentclass{standalone}
\usepackage{pgfplots}
% Nice color sets, see see http://colorbrewer2.org/
\usepgfplotslibrary{colorbrewer}
% initialize Set1-4 from colorbrewer (we're comparing 4 classes),
\pgfplotsset{compat = 1.15, cycle list/Set1-8}
% Tikz is loaded automatically by pgfplots
\usetikzlibrary{pgfplots.statistics, pgfplots.colorbrewer}
% provides \pgfplotstabletranspose
\usepackage{pgfplotstable}
\usepackage{filecontents}

\begin{filecontents*}{data.csv}
22, 26, 30, 17, 45
10, 15, 13, 12, 17
12, 30, 6,  57, 10
33, 38, 36, 25, 24
\end{filecontents*}

\begin{document}
\begin{tikzpicture}
% Boxplot groups columns, but we want rows
\pgfplotstabletranspose\datatransposed{\csvdata}
\begin{axis}[
boxplot/draw direction = y,
x axis line style = {opacity=0},
axis x line* = bottom,
axis y line = left,
enlarge y limits,
ymajorgrids,
xtick = {1, 2, 3, 4},
xticklabel style = {align=center, font=\small, rotate=60},
xticklabels = {Apples, Oranges, Bananas, Melons},
xtick style = {draw=none}, % Hide tick line
ylabel = {Juiciness},
ytick = {20, 40}
]
\foreach \n in {1,...,4} {
\addplot+[boxplot, fill, draw=black] table[y index=\n] {\datatransposed};
}
\end{axis}
\end{tikzpicture}
\end{document}


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