Table, siunitx, render + sign

Question

I have a table with number formatting through siunitx. In one column, I have values which show an improvement (or worsening) of one approach over another. To make it really clear, that I'm giving a delta there, I would like to explicitly show the + character for positive values (only for that one column). However, when I write it in my code, it is not rendered.

Minimal working example:

\documentclass[ngerman]{scrbook}
\usepackage{siunitx}
\begin{document}
\begin{tabular}{l *{3}{S[table-format=2.2]}}
    \hline
    {\textbf{Data}} &
    {\textbf{Baseline}} &
    {\textbf{Magic}} &
    {\textbf{$\Delta$}} \\ \hline
    Data A & 34.56 & 45.67 & +11.11 \\ % + character not rendered :(
    Data B & 76.54 & 98.76 & +22,22 \\
    Data C & 45.67 & 34.56 & -11,11 \\ \hline
\end{tabular}
\end{document}

Gives:

Instead, I would like +11.11 and +22.22 in the last column. Any hints appreciated.

Answer 1

You want retain-explicit-plus.

\documentclass[ngerman]{scrbook}
\usepackage{siunitx}
\begin{document}
\begin{tabular}{l *{3}{S[table-format=2.2,retain-explicit-plus]}}
    \hline
    {\textbf{Data}} &
    {\textbf{Baseline}} &
    {\textbf{Magic}} &
    {\textbf{$\Delta$}} \\ \hline
    Data A & 34.56 & 45.67 & +11.11 \\ % + character not rendered :(
    Data B & 76.54 & 98.76 & +22,22 \\
    Data C & 45.67 & 34.56 & -11,11 \\ \hline
\end{tabular}
\end{document}

Answer 2

Torbjørn has explained how to fix the problem but I would typeset the table as follows:

\documentclass{scrbook}

\usepackage{booktabs}
\usepackage{siunitx}

\begin{document}

\begin{center}
\begin{tabular}{
       l
  *{2}{S[table-format = 2.2]}
       S[table-format = -2.2, retain-explicit-plus]
}
  \toprule
    \multicolumn{1}{c}{{\textbf{Data}}} &
    {\textbf{Baseline}}                 &
    {\textbf{Magic}}                    &
    {$\Delta$}                      \\
  \midrule
    Data~A & 34.56 & 45.67 & +11.11 \\
    Data~B & 76.54 & 98.76 & +22.22 \\
    Data~C & 45.67 & 34.56 & -11.11 \\
  \bottomrule
\end{tabular}
\end{center}

\end{document}

Notice the use of table-format = -2.2 (instead of table-format = 2.2) to get the proper centering in the last column.

Also, notice the use of booktabs to get proper horizontal lines in the table.

Update

In case you also want a bold delta, you can use the following:

\documentclass{scrbook}

\usepackage{booktabs}
\usepackage{siunitx}

\begin{document}

\begin{center}
\begin{tabular}{
       l
  *{2}{S[table-format = 2.2]}
       S[table-format = -2.2, retain-explicit-plus]
}
  \toprule
    \multicolumn{1}{c}{{\textbf{Data}}} &
    {\textbf{Baseline}}                 &
    {\textbf{Magic}}                    &
    {$\mathbf{\Delta}$}             \\
  \midrule
    Data~A & 34.56 & 45.67 & +11.11 \\
    Data~B & 76.54 & 98.76 & +22.22 \\
    Data~C & 45.67 & 34.56 & -11.11 \\
  \bottomrule
\end{tabular}
\end{center}

\end{document}