[Tex/LaTex] Fraction ticks on a pgfplot

pgfplotstikz-pgf

I'm trying to use pgfplots to produce a plot with fractional ticks on the y-axis. Unfortunately pgfplots doesn't deal very nicely with things like yticks = {1/36, 1/18, 1/12, 1/9, 5/36, 1/6}, and gives various errors about how to represent them.

In the end, I got fed up and scaled my plot so that it passes through integer points instead. However, I'd still like to have the fractional ticks in their lowest form, because currently I have

Here is my code:

\documentclass{article}
\usepackage{pgfplots}

\begin{document}
   \pgfplotsset{
      standard/.style={
         axis x line=middle,
         axis y line=middle,
         enlarge x limits=0.15,
         enlarge y limits=0.15,
         every axis x label/.style={at={(1,0.1)},anchor=north west},
         every axis y label/.style={at={(0.1,1.1)},anchor=north},
         every axis plot post/.style={mark options={fill=white}}
      }
   }
   \begin{tikzpicture}
      \begin{axis}[
      standard,
      domain = 2:12,
      samples = 11,
      xlabel={$x$},
      ylabel={$\Pr(X=x)$},
      ymin=0,
      yticklabel={$\frac{\pgfmathprintnumber{\tick}}{36}$},
      ytick = {1, 2, 3, 4, 5, 6},
      ymax=6]
      \addplot+[ycomb,black,thick] {(6-abs(x-7))};
      \end{axis}
   \end{tikzpicture}
\end{document}

Is there a better way to go about the whole thing? I appreciate any help.

Best Answer

There are two possible options to achieve this:

Just need to write yticklabels={$1/36$, $1/18$, $1/12$, $1/9$, $5/36$, $1/6$} for simplified fractions (or yticklabels={$1/36$, $2/36$, $3/36$, $4/36$, $5/36$, $6/36$}, if you will), or with common fraction displaying by using yticklabels={$\frac{1}{36}$, $\frac{1}{18}$, $\frac{1}{12}$, $\frac{1}{9}$, $\frac{5}{36}$, $\frac{1}{6}$}. Or
write yticklabel={$\pgfmathprintnumber{\tick}/{36}$} instead of yticklabel={$\frac{\pgfmathprintnumber{\tick}}{36}$}.

Note, the difference between them is that with the first one, you write yticklabels=... and mention labels one by one at will (simplified or non simplified), and with the second one, you write yticklabel=... with the automatic generating code (but will display non simplified fractions).

Simplified fractions

Common fraction displaying

Non simplified fractions

Also, to place the ylabel above the vertical line and centered, you can put

every axis y label/.style={at={(current axis.above origin)},anchor=south},

And just to let you know, it is important to include the line

\pgfplotsset{compat=1.15}

in preamble when using PGFPlots. See this answer for further information.

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You can use

 y filter/.expression={y==0 ? nan : y}

in the options of \addplot.

\documentclass{article}

% ---------------------------------- tikz
\usepackage{pgfplots}          % to print charts
\pgfplotsset{compat=1.12}

\begin{document}

\begin{figure}
  \centering
  \begin{tikzpicture}
    \begin{axis} [
      % general
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grade   value
-11 0
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-9  0
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-7  0
-6  0
-5  3
-4  1
-3  2
-2  15
-1  11
0   179
1   8
2   1
3   0
4   1
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[Tex/LaTex] pgfplots: percentage in matrix plot

It does not work in your MWE because you are overwriting it by also giving the option nodes near coors to the \addplot command. Remove the latter one (or specify format here), and it will print. I added a thinspace before the percentage sign, although it can also be recommended to load the siunitx package and let that format and typeset the values for you.

Anyway, here's the quickfixed version:

\documentclass[border=3pt]{standalone}
\usepackage{pgfplots}
\pgfplotsset{%
  width=5cm,
  height=18cm,
  compat=1.13,
  colormap={blackwhite}{gray(0cm)=(1); gray(1cm)=(0.5)},
  xticklabels={LPIBG, ALL, HPIBG},
  xtick={0,...,2},
  ytick=\empty
}

\begin{document}
\begin{tikzpicture}
\begin{axis}[%
  enlargelimits=false,
  xlabel style={font=\footnotesize},
  ylabel style={font=\footnotesize},
  legend style={font=\footnotesize},
  xticklabel style={font=\footnotesize},
  yticklabel style={font=\footnotesize},
  colorbar,
  colorbar style={%
    ytick={0,20,40,60,80,100},
    yticklabels={0,20,40,60,80,100},
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  point meta min=0,
  point meta max=100,
  nodes near coords={\pgfmathprintnumber\pgfplotspointmeta\,\%},
  every node near coord/.append style={xshift=0pt,yshift=-7pt, black, font=\footnotesize},
]

\addplot[
matrix plot,
mesh/cols=3,
point meta=explicit]
table[meta=C]{
  x y C
  0 0 80
  1 0 36
  2 0 40
  0 1 64
  1 1 80
  2 1 60
  0 2 52
  1 2 84
  2 2 72
  0 3 72
  1 3 28
  2 3 32
  0 4 56
  1 4 84
  2 4 80
  0 5 72
  1 5 52
  2 5 44
  0 6 4
  1 6 84
  2 6 41
  0 7 37
  1 7 69
  2 7 84
  0 8 63
  1 8 53
  2 8 82
  0 9 78
  1 9 74
  2 9 39
  0 10 39
  1 10 63
  2 10 88
  0 11 76
  1 11 74
  2 11 49
  0 12 39
  1 12 6
  2 12 88
  0 13 46
  1 13 33
  2 13 75
  0 14 88
  1 14 67
  2 14 54
  0 15 79
  1 15 83
  2 15 75
  0 16 50
  1 16 46
  2 16 71
  0 17 92
  1 17 71
  2 17 75
  0 18 46
  1 18 33
  2 18 8
};
\end{axis}
\end{tikzpicture}
\end{document}