mjhjmtu

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
usepackagepgfplots
pgfplotssetcompat=1.16,width=15.5cm
usepackagecomment



begindocument
begintikzpicture
beginaxis[
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) ;

endaxis
endtikzpicture




enddocument

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
usepackagepgfplots
pgfplotssetcompat=1.16,width=17.5cm
usepackagecomment



begindocument
begintikzpicture
beginaxis[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) 
;

endaxis
endtikzpicture
enddocument

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

documentclass[tikz,border=3.15mm]standalone
usepackagepgfplots
pgfplotssetcompat=1.16,width=15.5cm
usepackagecomment

begindocument
begintikzpicture
beginaxis[
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) ;

endaxis
endtikzpicture

enddocument

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

documentclass[tikz,border=3.15mm]standalone
usepackagepgfplots
pgfplotssetcompat=1.16,width=15.5cm
usepackagepgfplotstable

newcommandmylabels% reserve global name

begindocument
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
pgfplotstablegetelem0labelofmytable% put labels into macro mylabels
xdefmylabelspgfplotsretval%
foreach i in 1,2,...,18pgfplotstablegetelemilabelofmytable
 xdefmylabelsmylabels,pgfplotsretval%

begintikzpicture
beginaxis[
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;
endaxis
endtikzpicture

enddocument

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
usepackagepgfplotstable
pgfplotssetcompat=1.16

begindocument
 begintikzpicture
 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

beginaxis[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 = mydataX,
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;

legendused,understood,not understood
endaxis
 endtikzpicture
enddocument

gives: