csvsimple - process column names with digits correctly

Question

I have a csv that contains column names with digits. Somehow this seems to be a problem for csvsimple, but I can't quite figure out why and how to deal with it correctly.

Here's what I want to achieve:

\documentclass{article}

\usepackage[utf8]{inputenc}
\usepackage{csvsimple}
\usepackage{filecontents}

\begin{filecontents*}{ndcgs.csv}
system;ndcg5;ndcg10;ndcg15;ndcg20;ndcg30;ndcg100;ndcg200;ndcg500;ndcg1000
A;0.632;0.566;0.531;0.533;0.511;0.475;0.396;0.301;0.301
B;0.646;0.615;0.598;0.588;0.563;0.536;0.517;0.401;0.363
C;0.557;0.567;0.589;0.576;0.573;0.511;0.478;0.429;0.380
D;0.644;0.577;0.538;0.540;0.518;0.473;0.398;0.303;0.302
E;0.291;0.304;0.302;0.330;0.351;0.361;0.281;0.238;0.236
\end{filecontents*}

\begin{document}

\csvstyle{myTableStyle}{tabular=lc,
table head=\toprule system & ndcg5\\\midrule,
table foot=\bottomrule,
head to column names,
separator=semicolon}

\csvreader[myTableStyle]{ndcgs.csv}{}%
    {\system & \ndcg5}

\end{document}

The error message complains about an undefined control sequence, related to the column name "ndcg5":

! Undefined control sequence.
\csv@tablehead ->\toprule 
                      system & ndcg5\\\midrule 
l.25         {\system & \ndcg5}

I tried to prevent this by using \csvcolii etc but still the same error.

I found that the following works:

\documentclass{article}

\usepackage[utf8]{inputenc}
\usepackage{csvsimple}
\usepackage{filecontents}

\begin{filecontents*}{ndcgs.csv}
system;ndcg5;ndcg10;ndcg15;ndcg20;ndcg30;ndcg100;ndcg200;ndcg500;ndcg1000
A;0.632;0.566;0.531;0.533;0.511;0.475;0.396;0.301;0.301
B;0.646;0.615;0.598;0.588;0.563;0.536;0.517;0.401;0.363
C;0.557;0.567;0.589;0.576;0.573;0.511;0.478;0.429;0.380
D;0.644;0.577;0.538;0.540;0.518;0.473;0.398;0.303;0.302
E;0.291;0.304;0.302;0.330;0.351;0.361;0.281;0.238;0.236
\end{filecontents*}

\begin{document}

\begin{tabular}{lc}%
\bfseries system & \bfseries ndcg-5%
    \csvreader[separator=semicolon]{ndcgs.csv}{}%
     {\\ \csvcoli & \csvcolii}%
 \end{tabular}

\end{document}

But I don't see how this approach would allow me to define the table layout (regarding toprule, midrule etc.) in the same way as in the example above.

Can anyone help?

Answer 1

You can't use names with numbers as a macro to indicate the column names simply because you can't use numbers in TeX macros, see here: https://texfaq.org/FAQ-linmacnames.

Your problem, however, is easily solvable with \csvcoli..., two examples follow.

\documentclass{article}

\usepackage[utf8]{inputenc}
\usepackage{csvsimple}
\usepackage{booktabs}

\usepackage{filecontents}
\begin{filecontents*}{ndcgs.csv}
system;ndcg5;ndcg10;ndcg15;ndcg20;ndcg30;ndcg100;ndcg200;ndcg500;ndcg1000
A;0.632;0.566;0.531;0.533;0.511;0.475;0.396;0.301;0.301
B;0.646;0.615;0.598;0.588;0.563;0.536;0.517;0.401;0.363
C;0.557;0.567;0.589;0.576;0.573;0.511;0.478;0.429;0.380
D;0.644;0.577;0.538;0.540;0.518;0.473;0.398;0.303;0.302
E;0.291;0.304;0.302;0.330;0.351;0.361;0.281;0.238;0.236
\end{filecontents*}

\begin{document}

First method, table formatting as \verb|\csvreader| options:

\csvstyle{myTableStyle}{tabular=lc,
table head=\toprule \bfseries system & \bfseries ndcg-5\\\midrule,
table foot=\bottomrule,
head to column names,
separator=semicolon}
\begin{center}
\csvreader[myTableStyle]{ndcgs.csv}{}%
    {\csvcoli & \csvcolii}
\end{center}    

Second method, \verb|tabular| with a \verb|\csvreader| inside:

\begin{center}
\begin{tabular}{lc}
\toprule
\bfseries system & \bfseries ndcg-5 \\
\midrule\csvreader[separator=semicolon, late after line=\\]{ndcgs.csv}{}%
     {\csvcoli & \csvcolii}
\bottomrule
\end{tabular}
\end{center} 

\end{document}