Cfrgtkky

I have prepared a code including some data resulting in a bar plot. I want to use a mathematical expression as xticklabels but my code does not work. How can I figure this point out?

Here is my code:

documentclass[tikz,border=3.15mm]{standalone}

usepackage{pgfplots}

pgfplotsset{compat=1.16,width=15.5cm}

usepackage{comment}







begin{document}

begin{tikzpicture}

begin{axis}[

ybar,

xticklabels={

    {$ 10_g to 8_g $}, {$ 8_g to 6_g $}, {$ 6_g to 4_g $}, {$ 4_g to 2_g $}, 

    {$ 8_g to 8gamma $}, {$ 6_g to 6gamma $}, {$ 4_g to 4gamma $}, { $ 2_g to 2gamma $}, 

    {$ 7_gamma to 8_g $}, {$ 5_gamma to 6_g $}, {$ 3_gamma to 4_g $}, 

    {$ 8_gamma to 6_gamma $}, {$ 6_gamma to 4_gamma $}, {$ 4_gamma to 2_gamma $}, 

    {$ 7_gamma to 5_gamma $}, {$ 5_gamma to 3_gamma $},

    {$ 7_gamma to 6_gamma $}, {$ 5_gamma to 4_gamma $}, {$ 3_gamma to 2_gamma $}

},

x tick label style={rotate=90},

enlarge x limits=0.1,

legend style={at={(0.85,1)},

anchor=north,legend columns=-1},

bar width = 0.2 cm,

symbolic x coords={10gto8g, 8gto6g, 6gto4g, 4gto2g, 8gto8gamma, 6gto6gamma, 4gto4gamma, 2gto2gamma, 7gammato8g, 5gammato6g, 3gammato4g, 8gammato6gamma, 6gammato4gamma, 4gammato2gamma,  7gammato5gamma,  5gammato3gamma,  7gammato6gamma,  5gammato4gamma,  3gammato2gamma},

xtick=data,

nodes near coords={pgfmathprintnumber[precision=3]{pgfplotspointmeta}},

nodes near coords align={vertical},

nodes near coords style={rotate=90,anchor=west,font=small}

]         





addplot+[bar shift = -0.25cm] coordinates {(10gto8g,0) (8gto6g,0) (6gto4g,0) (4gto2g,0) (8gto8gamma,0) (6gto6gamma,0) (4gto4gamma,0) (2gto2gamma,0) (7gammato8g,0) (5gammato6g,0) (3gammato4g,0) (8gammato6gamma,0) (6gammato4gamma,0) (4gammato2gamma,0) (7gammato5gamma,0) (5gammato3gamma,0) (7gammato6gamma,0) (5gammato4gamma,0) (3gammato2gamma,0) };





addplot+[bar shift = 0cm] coordinates {(10gto8g,0) (8gto6g,0) (6gto4g,0) (4gto2g,0) (8gto8gamma,0) (6gto6gamma,0) (4gto4gamma,0) (2gto2gamma,0) (7gammato8g,0) (5gammato6g,0) (3gammato4g,0) (8gammato6gamma,0) (6gammato4gamma,0) (4gammato2gamma,0) (7gammato5gamma,0) (5gammato3gamma,0) (7gammato6gamma,0) (5gammato4gamma,0) (3gammato2gamma,0) };



addplot+[bar shift = 0.25cm] coordinates coordinates {(10gto8g,2.967) (8gto6g,2.635) (6gto4g,2.203) (4gto2g,1.590) (8gto8gamma,0.1290) (6gto6gamma,0.1976) (4gto4gamma,0.3481) (2gto2gamma,1.620) (7gammato8g,0.808) (5gammato6g,0.972) (3gammato4g,1.243) (8gammato6gamma,1.590) (6gammato4gamma,1.031) (4gammato2gamma,0.736) (7gammato5gamma,1.851) (5gammato3gamma,1.235) (7gammato6gamma,1.260) (5gammato4gamma,1.313) (3gammato2gamma,2.171) };



end{axis}

end{tikzpicture}









end{document}

Many thanks.

There were two issues:

1. in the last plot you had coordinates twice.


2. for some reason, pgfplots does not like a to. The deeper reason can be presumably found in pgfplots.code.tex, where to is used in many macros.

I acknowledge that John Kormylo beat me by seconds (while I was typing the explanation).

documentclass[tikz,border=3.15mm]{standalone}

usepackage{pgfplots}

pgfplotsset{compat=1.16,width=17.5cm}

usepackage{comment}







begin{document}

begin{tikzpicture}

begin{axis}[ybar,

 x tick label style={rotate=90},

 enlarge x limits=0.04,

 legend style={at={(0.85,1)},

 anchor=north,legend columns=-1},

 bar width=0.2cm,

 xtick=data,

 symbolic x coords={10gto8g,8gto6g,6gto4g,4gto2g,8gto8gamma,6gto6gamma,4gto4gamma,2gto2gamma,7gammato8g,5gammato6g,3gammato4g,8gammato6gamma,6gammato4gamma,4gammato2gamma,7gammato5gamma,5gammato3gamma,7gammato6gamma,5gammato4gamma,3gammato2gamma},

 xticklabels={

 {$10_grightarrow8_g$},{$8_grightarrow6_g$},{$6_grightarrow4_g$},{$4_grightarrow2_g$},

 {$8_grightarrow8gamma$},{$6_grightarrow6gamma$},{$4_grightarrow4gamma$},{$2_grightarrow2gamma$},

 {$7_gammarightarrow8_g$},{$5_gammarightarrow6_g$},{$3_gammarightarrow4_g$},

 {$8_gammarightarrow6_gamma$},{$6_gammarightarrow4_gamma$},{$4_gammarightarrow2_gamma$},

 {$7_gammarightarrow5_gamma$},{$5_gammarightarrow3_gamma$},

 {$7_gammarightarrow6_gamma$},{$5_gammarightarrow4_gamma$},

 {$3_gammarightarrow2_gamma$}

 },

 nodes near coords={pgfmathprintnumber[precision=3]{pgfplotspointmeta}},

 nodes near coords align={vertical},

 nodes near coords style={rotate=90,anchor=west,font=small}

]         





addplot+[bar shift = -0.25cm] 

coordinates {(10gto8g,0)

 (8gto6g,0) (6gto4g,0) (4gto2g,0) (8gto8gamma,0) (6gto6gamma,0) (4gto4gamma,0) (2gto2gamma,0) (7gammato8g,0) (5gammato6g,0) (3gammato4g,0) (8gammato6gamma,0) (6gammato4gamma,0) (4gammato2gamma,0) (7gammato5gamma,0) (5gammato3gamma,0) (7gammato6gamma,0) (5gammato4gamma,0) (3gammato2gamma,0)

};

% 

% 

addplot+[bar shift = 0cm] coordinates {(10gto8g,0) (8gto6g,0) (6gto4g,0) (4gto2g,0) (8gto8gamma,0) (6gto6gamma,0) (4gto4gamma,0) (2gto2gamma,0) (7gammato8g,0) (5gammato6g,0) (3gammato4g,0) (8gammato6gamma,0) (6gammato4gamma,0) (4gammato2gamma,0) (7gammato5gamma,0) (5gammato3gamma,0) (7gammato6gamma,0) (5gammato4gamma,0) (3gammato2gamma,0) };

% 

% % Z5 coordinate was in twice

addplot+[bar shift = 0.25cm] coordinates {(10gto8g,2.967) 

(8gto6g,2.635) (6gto4g,2.203) (4gto2g,1.590) (8gto8gamma,0.1290) (6gto6gamma,0.1976) (4gto4gamma,0.3481) (2gto2gamma,1.620) (7gammato8g,0.808) (5gammato6g,0.972) (3gammato4g,1.243) (8gammato6gamma,1.590) (6gammato4gamma,1.031) (4gammato2gamma,0.736) (7gammato5gamma,1.851) (5gammato3gamma,1.235) (7gammato6gamma,1.260) (5gammato4gamma,1.313) 

(3gammato2gamma,2.171) 

};



end{axis}

end{tikzpicture}

end{document}

Tikz redefines to. Use rightarrow instead. Also, it seems that symbolic x coordinates and xticklables are incompatible.

documentclass[tikz,border=3.15mm]{standalone}

usepackage{pgfplots}

pgfplotsset{compat=1.16,width=15.5cm}

usepackage{comment}



begin{document}

begin{tikzpicture}

begin{axis}[

ybar,

xtick=data,

x tick label style={rotate=90},

enlarge x limits=0.1,

legend style={at={(0.85,1)},

  anchor=north,legend columns=-1},

bar width = 0.2 cm,

nodes near coords={pgfmathprintnumber[precision=3]{pgfplotspointmeta}},

nodes near coords align={vertical},

nodes near coords style={rotate=90,anchor=west,font=small},

xticklabels={

    {$ 10_g rightarrow 8_g $}, {$ 8_g rightarrow 6_g $}, {$ 6_g rightarrow 4_g $}, {$ 4_g rightarrow 2_g $}, 

    {$ 8_g rightarrow 8gamma $}, {$ 6_g rightarrow 6gamma $}, {$ 4_g rightarrow 4gamma $}, {$ 2_g rightarrow 2gamma $}, 

    {$ 7_gamma rightarrow 8_g $}, {$ 5_gamma rightarrow 6_g $}, {$ 3_gamma rightarrow 4_g $}, 

    {$ 8_gamma rightarrow 6_gamma $}, {$ 6_gamma rightarrow 4_gamma $}, {$ 4_gamma rightarrow 2_gamma $}, 

    {$ 7_gamma rightarrow 5_gamma $}, {$ 5_gamma rightarrow 3_gamma $},

    {$ 7_gamma rightarrow 6_gamma $}, {$ 5_gamma rightarrow 4_gamma $}, {$ 3_gamma rightarrow 2_gamma $}

},

]         



addplot+[bar shift = -0.25cm] coordinates {(1,0) (2,0) (3,0) (4,0) (5,0) (6,0) (7,0) (8,0) (9,0) (10,0) (11,0) (12,0) (13,0) (14,0) (15,0) (16,0) (17,0) (18,0) (19,0) };



addplot+[bar shift = 0cm] coordinates {(1,0) (2,0) (3,0) (4,0) (5,0) (6,0) (7,0) (8,0) (9,0) (10,0) (11,0) (12,0) (13,0) (14,0) (15,0) (16,0) (17,0) (18,0) (19,0) };



% Z5

addplot+[bar shift = 0.25cm] coordinates {(1,2.967) (2,2.635) (3,2.203) (4,1.590) (5,0.1290) (6,0.1976) (7,0.3481) (8,1.620) (9,0.808) (10,0.972) (11,1.243) (12,1.590) (13,1.031) (14,0.736) (15,1.851) (16,1.235) (17,1.260) (18,1.313) (19,2.171) };



end{axis}

end{tikzpicture}



end{document}

It occurred to me that it might be better to record the data in table format.

documentclass[tikz,border=3.15mm]{standalone}

usepackage{pgfplots}

pgfplotsset{compat=1.16,width=15.5cm}

usepackage{pgfplotstable}



newcommand{mylabels}{}% reserve global name



begin{document}

pgfplotstableread[col sep=comma, string type]{

x, name, label, y1, y2, y3

1, 10gto8g, $10_g rightarrow 8_g$, 0,0,2.967

2, 8gto6g, $8_g rightarrow 6_g$, 0,0,2.635

3, 6gto4g, $6_g rightarrow 4_g$, 0,0,2.203

4, 4gto2g, $4_g rightarrow 2_g$, 0,0,1.590

5, 8gto8gamma, $8_g rightarrow 8gamma$, 0,0,0.1290

6, 6gto6gamma, $6_g rightarrow 6gamma$, 0,0,0.1976

7, 4gto4gamma, $4_g rightarrow 4gamma$, 0,0,0.3481

8, 2gto2gamma, $2_g rightarrow 2gamma$, 0,0,1.620

9, 7gammato8g, $7_gamma rightarrow 8_g$, 0,0,0.808

10, 5gammato6g, $5_gamma rightarrow 6_g$, 0,0,0.972

11, 3gammato4g, $3_gamma rightarrow 4_g$, 0,0,1.243

12, 8gammato6gamma, $8_gamma rightarrow 6_gamma$, 0,0,1.590

13, 6gammato4gamma, $6_gamma rightarrow 4_gamma$, 0,0,1.031

14, 4gammato2gamma, $4_gamma rightarrow 2_gamma$, 0,0,0.736

15, 7gammato5gamma, $7_gamma rightarrow 5_gamma$, 0,0,1.851

16, 5gammato3gamma, $5_gamma rightarrow 3_gamma$, 0,0,1.235

17, 7gammato6gamma, $7_gamma rightarrow 6_gamma$, 0,0,1.260

18, 5gammato4gamma, $5_gamma rightarrow 4_gamma$, 0,0,1.313

19, 3gammato2gamma, $3_gamma rightarrow 2_gamma$, 0,0,2.171

}mytable



%pgfplotstabletypeset[string type]mytable% error check

pgfplotstablegetelem{0}{label}ofmytable% put labels into macro mylabels

xdefmylabels{pgfplotsretval}%

foreach i in {1,2,...,18}{pgfplotstablegetelem{i}{label}ofmytable

  xdefmylabels{mylabels,pgfplotsretval}}%



begin{tikzpicture}

begin{axis}[

ybar,

xtick=data,

x tick label style={rotate=90},

enlarge x limits=0.1,

legend style={at={(0.85,1)},

  anchor=north,legend columns=-1},

bar width = 0.2 cm,

nodes near coords={pgfmathprintnumber[precision=3]{pgfplotspointmeta}},

nodes near coords align={vertical},

nodes near coords style={rotate=90,anchor=west,font=small},

xticklabels/.expand once=mylabels

]         



addplot+[bar shift = -0.25cm] table[x=x, y=y1] mytable;

addplot+[bar shift = 0cm] table[x=x, y=y2] mytable;

addplot+[bar shift = 0.25cm] table[x=x, y=y3] mytable;

end{axis}

end{tikzpicture}



end{document}

with use of pgfplotstable you will not have problem with use of to math symbol. beside this code is simpler, a bit shorter and to my opinion more clear. based on my answer on your previous question, i rewrite your mwe to:

documentclass[margin=3mm]{standalone}

usepackage{pgfplotstable}

pgfplotsset{compat=1.16}



begin{document}

    begin{tikzpicture}

    pgfplotstableread{

X                       Y1  Y2  Y3

$10_gto 8_g$           0   0   2.967

$8_gto 6_g$            0   0   2.635

$6_gto 4_g$            0   0   2.203

$4_gto 2_g$            0   0   1.590

$8_gto 8gamma$        0   0   0.1290

$6_gto 6gamma$        0   0   0.1976

$4_gto 4gamma$        0   0   0.3481

$2_gto 2gamma$        0   0   1.6204

$8_gammato 6_gamma$  0   0   1.590

$6_gammato 4_gamma$  0   0   1.031

$4_gammato 2_gamma$  0   0   0.736

$8_gammato 6_gamma$  0   0   1.590

$6_gammato 4_gamma$  0   0   1.031

$4_gammato 2_gamma$  0   0   0.736

$7_gammato 5_gamma$  0   0   1.851

$5_gammato 3_gamma$  0   0   1.235

$7_gammato 6_gamma$  0   0   1.260

$5_gammato 4_gamma$  0   0   1.313

$3_gammato 2_gamma$  0   0   2.171   

    }mydata



begin{axis}[width=160mm,

enlarge x limits=0.04,

enlarge y limits=0.01,

legend style={legend columns=-1,

%              legend pos=north east,

              font=footnotesize,

              /tikz/every even column/.append style={column sep=2mm},

              anchor=north,

              at={(0.5,-0.12)},

              },

ybar=0.4mm,     % distance between bars (shift bar)

bar width=1.8mm,  % width of bars

nodes near coords={pgfmathprintnumber[precision=3]{pgfplotspointmeta}},

nodes near coords style={font=scriptsize, inner sep=2pt, rotate=90, anchor=west},

nodes near coords align={vertical},

ymin=0, ymax=3.5,

ytick={0,0.5,...,3.5},

%

xtick=data,

xticklabels from table = {mydata}{X},

x tick label style={rotate=90, anchor=east},

scale only axis,

    ]

addplot table[x expr=coordindex,y index=1] {mydata};

addplot table[x expr=coordindex,y index=2] {mydata};

addplot table[x expr=coordindex,y index=3] {mydata};



legend{used,understood,not understood}

end{axis}

    end{tikzpicture}

end{document}

gives: