Automatic amount table columns and column numbers

Question

I'm looking for a way to create a command with which Latex can automatically generate a table with a given amount of columns, and automatically fills in the column numbers as headers.

I'm looking for something like this:

\newcommand{\CountBox}[1]{
    \begin{flushright}
        \begin{tabular}{*{#1}{|l}}
        \hline
        \multicolumn{1}{|c|}{1} #1  \\ \hline
                                #1   \\ \hline
        \end{tabular}   
    \end{flushright}
}

Where the following command creates the following table:

\CountBox{6}

And the following command creates the following table:

\CountBox{3}

I seem to get stuck on having to manually input the ampersands into the multicolumn command (have tried \loop, \while, and \expandafter)

Thanks for the help!

Just in case the original code for the 6 column table:

\begin{flushright}
    \begin{tabular}{*{7}{|l}}
    \hline
    \multicolumn{1}{|c|}{1} & 2 & 3 & 4 & 5 & 6 \\ \hline 
                            &   &   &   &   &   \\ \hline

    \end{tabular}   
\end{flushright}

https://tex.stackexchange.com/questions/165625/how-to-fill-a-dynamically-generated-table-with-dynamic-content might be helpful — samcarter_is_at_topanswers.xyz, Jan 04 '19 at 15:25
any reason for centering the 1 in its cell and not the others ? — , Jan 04 '19 at 18:40

score 5 · Answer 1 · answered Jan 04 '19 at 16:25

Here is an expl3 implementation. With the help of array and its w column specifier, all columns can be made as wide as the last (with the largest number).

\documentclass{article}

\usepackage{xparse,array}

\ExplSyntaxOn
\NewDocumentCommand{\CountBox}{m}
 {
  % measure the wider number
  \hbox_set:Nn \l_tmpa_box { #1 }
  \dim_set:Nn \l_tmpa_dim { \box_wd:N \l_tmpa_box }
  % do as many columns as specified
  \begin{tabular}{|*{#1}{w{c}{\l_tmpa_dim}|}}
  \hline
  % do '<number> &' one less than specified, then add the last number
  \int_step_function:nN { #1 - 1 } \__phlemp_countbox_head:n #1 \\
  \hline
  % generate as many &'s as necessary to fill the second row
  \prg_replicate:nn { #1 - 1 } { & } \\
  \hline
  \end{tabular}
 }

% auxiliary function for adding the & after the number
\cs_new_protected:Nn \__phlemp_countbox_head:n { #1 & }
\ExplSyntaxOff

\begin{document}

\CountBox{3} \CountBox{10}

\end{document}

Thanks for the quick response! It produced a lot of illegal pream-tokens on my side though (working in Overleaf). Also did not allow the _ outside of math-mode, and an undefined control sequence on " \int_step_function:nN ". Is that something I can fix or have to install something for? Much appreciated. — Phlemp, Jan 05 '19 at 14:23

score 3 · Answer 2 · answered Jan 04 '19 at 16:34

The following uses multido to generate the column numbering sequence and blank row. A similar approach to egreg's uses array's w{<align>}{<width>} to set the column width to the widest element:

\documentclass{article}

\usepackage{multido,array}

\newcounter{boxCount}
\newlength{\boxCountwd}

\makeatletter
\newcommand{\CountBox}[1]{%
  \setcounter{boxCount}{0}% Reset boxCount
  \settowidth{\boxCountwd}{#1}% Measure widest element
  \def\CountBoxSeq{\@gobble}%
  \def\CountBoxSeqPhantom{\@gobble}%
  \multido{\i=1+1}{#1}{%
    \xdef\CountBoxSeq{\CountBoxSeq & \i}%
    \xdef\CountBoxSeqPhantom{\CountBoxSeqPhantom &}%
  }%
  \noindent
  \begin{tabular}{ *{#1}{|w{c}{\boxCountwd}} | }
    \hline
    \CountBoxSeq \\
    \hline
    \CountBoxSeqPhantom \\
    \hline
  \end{tabular}%
}
\makeatother

\begin{document}

\CountBox{5}

\end{document}

Thanks for the reply! When I try compiling it produces illegal pream tokens on the "w" and on the "\boxCountwd" in the tabular. I don't know how to fix it. Working in Overleaf. Really appreciate your help! — Phlemp, Jan 05 '19 at 14:25
@Phlemp: Did you add \usepackage{array} to your preamble like I did? Probably not. You don't have to use w{c}{..} as a column specification. It just aids in making the column widths the same if you have 10 or more columns. Alternatively, just use c, l or r. — Werner, Jan 05 '19 at 17:22

score 2 · Accepted Answer · answered Jan 04 '19 at 21:31

With \foreach in TikZ:

\documentclass{article}       
\usepackage{tikz}
\usepackage{etoolbox}
\usetikzlibrary{
    positioning,
    shapes.multipart
    }
\tikzset{
    mynode/.style={
        draw,
        rectangle split,
        rectangle split parts=2,
        text centered,
    },
}
\newcommand{\CountBox}[1]{%
    \begin{tikzpicture}
        \node[mynode] (1) {1};
        \ifnumcomp{#1}{=}{1}{}{%
            \foreach \mynum 
                [evaluate=\mynum as \myprev using int(\mynum-1)]  
                in {2,...,#1}
            \node[mynode,xshift=-\pgflinewidth,anchor=west] (\mynum) at (\myprev.east) {\mynum};
            }%
    \end{tikzpicture}%
    }

\begin{document}
\CountBox{1} 

\CountBox{3}

\CountBox{6}

\CountBox{2} 
\CountBox{4}
\CountBox{7} 
\end{document}

Thank you for the response! Works like a charm. – Phlemp Jan 05 '19 at 14:19 — Phlemp, Jan 05 '19 at 14:19
@Phlemp You're welcome, thank you for accepting my answer! – CarLaTeX Jan 05 '19 at 16:33 — CarLaTeX, Jan 05 '19 at 16:33

Automatic amount table columns and column numbers

3 Answers3