longtable, siunitx, multirow, multicolumn, textsuperscript combination problem

Question

I have the table below with, \multirow, \multicolumn and \textsuperscript calls. I would like to have all entries centered, and the numerical entries additionally "scientifically" aligned right (as done by the siunitx package). For the time being I use \rlap, but that only aligns the text superscripts, not the numerical entries. Ideally, I should use something like the siunitx package, and in principle it should automatically align the textsuperscripts, but I am having trouble combining the siunitx package with my current code. Can anyone help?

\begin{center}

\renewcommand{\arraystretch}{1.5}

\begin{tiny}

\begin{longtable}{ccc}
\caption{...}\label{tab:1}\\
\hline
Text & Text & $X$\\
     &      & $\mathrm{\left[\%\right]}$\\
\hline
\endfirsthead
\multicolumn{3}{l}%
{\tablename\ \thetable\ (\emph{continued from previous page})} \\
\hline
Text & Text & $X$\\
     &      & $\mathrm{\left[\%\right]}$\\
\hline
\endhead
\hline 
\multicolumn{3}{r}%
{(\emph{continued on next page})} \\
\endfoot
\hline
\\
\multicolumn{3}{l}%
{\shortstack[l]{\textsuperscript{a}Method 1\\
\textsuperscript{b}Remark}}
\endlastfoot

Text & Text & 70.5\rlap{\textsuperscript{a}}\\
     & Text & 8.8\rlap{\textsuperscript{a}}\\
     & Text & 78.1\rlap{\textsuperscript{a}}\\
     & Text & 7.0\rlap{\textsuperscript{a}}\\
     & Text & 76.5\rlap{\textsuperscript{a}}\\
     & Text & 92.5\rlap{\textsuperscript{a,b}}\\
Text & \multirow{2}{*}{text} & \multirow{2}{*}{8.71\rlap{\textsuperscript{a}}}\\
Text &      &\\

Text & Text & 79.2\rlap{\textsuperscript{a}}\\
     & Text & 69.0\rlap{\textsuperscript{a}}\\
     & Text & 65.2\rlap{\textsuperscript{a}}\\
     & Text & 77.7\rlap{\textsuperscript{a}}\\
     & Text & 69.7\rlap{\textsuperscript{a,b}}\\
     & Text & 67.6\rlap{\textsuperscript{a}}\\
     &      &\\
\cdashline{1-3}
\multicolumn{2}{c}%
{\textbf{Mean}} & 76.35\\
\multicolumn{2}{c}%
{(SD)}          & (7.82)\\

\end{longtable}

\end{tiny}
\end{center}

Here the shortened MWE combining \multirow with \tablenum, to achieve the same alignment, but with larger space between the two rows than with \makecell:

\documentclass{article}

\usepackage{longtable}
\usepackage{siunitx}
\usepackage{booktabs}
\usepackage{arydshln}

\usepackage{makecell}

\usepackage{multirow}


\begin{document}

\renewcommand{\arraystretch}{1.5}


\begin{longtable}{ccc}

\caption{...}\label{tab:1}\\

\hline
Text & Text & $X$\\
     &      & [\%]\\ 
\hline
\endfirsthead
\multicolumn{3}{l}{\tablename\ \thetable\ (\emph{continued from previous page})} \\
\hline
Text & Text &  $X$\\
     &      &  [\%]\\
\hline
\endhead
\hline 
\multicolumn{3}{r}{(\emph{continued on next page})} \\
\endfoot
\hline
\multicolumn{3}{l}%
{\shortstack[l]{\textsuperscript{a}Method 1\\
\textsuperscript{b}Remark 1}}
\endlastfoot

\multirow{ 1}{*}{Ttext} & \multirow{ 1}{*}{Ttext} & \multirow{ 1}{*}{\tablenum[table-format = 2.1]{70.5}\rlap{\textsuperscript{a,b}}}\\
Ttext & \multirow{ 2}{*}{Ttext} & \multirow{ 2}{*}{\tablenum[table-format = 2.1]{8.7}\rlap{\textsuperscript{a}}}\\
Ttext & &\\
\cdashline{1-3}
\multicolumn{2}{c}{\textbf{Mean}} &  \multirow{ 1}{*}{\tablenum[table-format = 2.1]{76.3}}\\
\multicolumn{2}{c}{(SD)}          &  \multirow{ 1}{*}{\tablenum[table-format = 2.1,input-symbols=()]{(7.8)}}\\

\end{longtable}

\end{document}

Answer 1

Maybe you are looking for something like the following:

\documentclass{article}

\usepackage{longtable}
\usepackage{siunitx}
\usepackage{booktabs}
\usepackage{arydshln}
\usepackage{threeparttablex}
\usepackage{makecell}

\begin{document}


\renewcommand{\arraystretch}{1.5}

\begin{ThreePartTable}
  \begin{TableNotes}
     \item[a] Method 1
     \item[b] Remark
  \end{TableNotes}
\begin{longtable}{ccS[table-format=2.2,input-symbols=()]}
    \caption{...}\label{tab:1}\\
  \toprule
  Text & Text & $X$\\
       &      & [\%]\\
  \midrule
\endfirsthead
  \multicolumn{3}{l}{\tablename\ \thetable\ (\emph{continued from previous page})} \\
  \hline
  Text & Text &  $X$\\
       &      &  [\%]\\
  \midrule
\endhead
  \hline 
  \multicolumn{3}{r}{(\emph{continued on next page})} \\
\endfoot
  \hline
  \insertTableNotes
\endlastfoot

Text & Text & 70.5\tnote{a}\\
     & Text & 8.8\tnote{a}\\
     & Text & 78.1\tnote{a}\\
     & Text & 7.0\tnote{a}\\
     & Text & 76.5\tnote{a}\\
     & Text & 92.5\tnote{a,b}\\
\makecell{Text \\Text} & text & 8.71\tnote{a}\\

Text & Text & 79.2\tnote{a}\\
     & Text & 69.0\tnote{a}\\
     & Text & 65.2\tnote{a}\\
     & Text & 77.7\tnote{a}\\
     & Text & 69.7\tnote{a}\\
     & Text & 67.6\tnote{a}\\

\cdashline{1-3}
\multicolumn{2}{c}{\textbf{Mean}} & 76.35\\
\multicolumn{2}{c}{(SD)}          & (7.82)\\

\end{longtable}
\end{ThreePartTable}

\end{document}

I have used siunitx's S column with an appropriate table-format option in order to align the numbers with respect to the decimal separator.

For the notes, I have used the threeparttablex package and its ThreePartTable and TableNotes environments, as well as the \tnote command.

Additionally, I have replaced the \hlines by rules from the booktabs package.

I have also replaced the \multirow commands by a makecell command in the first column in order to achieve a similar layout without destroying the alignment in this particular row.

Lastly, I have removed the center environment as longtables are centered by default. From the longtable documentation:

The optional argument of longtable controls the horizontal alignment of the table. The possible options are [c] , [r] and [l] , for centring, right and left adjustment, respectively. Normally centring is the default,[...]