[Tex/LaTex] Split the title of a table into more than one row

spacingtables

Suppose I had the following;

\begin{table}
\centering
\begin{tabular}{|c|c|}
\hline
\multicolumn{2}{|c|}{Table1}  \\ \hline
A very long equation with k as input & Answer \\ \hline
1 & -19.0123  \\ \hline
2 & -16.4377 \\ \hline
3 & -13.3349 \\ \hline
4 & -11.7427  \\ \hline
5 & -10.1329 \\ \hline
6  & -9.0075 \\ \hline
7 & -6.0001 \\ \hline
\end{tabular}
\quad
\begin{tabular}{|c|c|}
\hline
\multicolumn{2}{|c|}{table2}  \\ \hline
A very long equation with k as input & Answer \\ \hline
1 & -16.0123  \\ \hline
2 & -12.4377 \\ \hline
3 & -9.5532 \\ \hline
4 & -5.7427  \\ \hline
5 & -4.1329 \\ \hline
6  & -3.0075 \\ \hline
7 & -3.0001 \\ \hline
\end{tabular}
\quad
\begin{tabular}{|c|c|}
\hline
\multicolumn{2}{|c|}{table3}  \\ \hline
A very long equation with k as input & Answer \\ \hline
1 & -5.0123  \\ \hline
2 & -2.4377 \\ \hline
3 & -3.3349 \\ \hline
4 & -1.7427  \\ \hline
5 & -1.1329 \\ \hline
6  & -1.0075 \\ \hline
7 & -1.0001 \\ \hline
\end{tabular}
\end{table}

Notice how the first columns only have small entries (At most they will have 8 figures), I was wondering what I could insert in this to make it so that that the title of column 1 (the long equation with k as input) would split into more than one row – whilst remaining centred.

Thanks – and apologies if this has already been answered,
Rob.

EDIT: The end idea is to ensure all tables are next to one another on the same row.

Best Answer

You can load array package and declare a new column type

\newcolumntype{C}{@{}>{\Centering\arraybackslash}m{0.14\linewidth}}

with suitable value for 0.14 in 0.14\linewidth. I have used \Centering command from ragged2e package inside the column. Also you will need [t] for tabular as in 

 \begin{tabular}[t]{|C|c|}

MWE

\documentclass{article}
\usepackage{amsmath,array,ragged2e}
\newcolumntype{C}{>{\Centering\arraybackslash}m{0.14\linewidth}}
\begin{document}
  \begin{table}
\centering
\begin{tabular}[t]{|C|c|}
\hline
\multicolumn{2}{|c|}{Table1}  \\ \hline
A very long equation with k as input & Answer \\ \hline
1 & -19.0123  \\ \hline
2 & -16.4377 \\ \hline
3 & -13.3349 \\ \hline
4 & -11.7427  \\ \hline
5 & -10.1329 \\ \hline
6  & -9.0075 \\ \hline
7 & -6.0001 \\ \hline
\end{tabular}
%\quad
\begin{tabular}[t]{|C|c|}
\hline
\multicolumn{2}{|c|}{table2}  \\ \hline
A very long equation with k as input & Answer \\ \hline
1 & -16.0123  \\ \hline
2 & -12.4377 \\ \hline
3 & -9.5532 \\ \hline
4 & -5.7427  \\ \hline
5 & -4.1329 \\ \hline
6  & -3.0075 \\ \hline
7 & -3.0001 \\ \hline
\end{tabular}
%\quad
\begin{tabular}[t]{|C|c|}
\hline
\multicolumn{2}{|c|}{table3}  \\ \hline
$a+b+f+c+d+g+t+r+e+y+u+h+g+b+u+y+u+r+t+y=Z$ & Answer \\ \hline
1 & -5.0123  \\ \hline
2 & -2.4377 \\ \hline
3 & -3.3349 \\ \hline
4 & -1.7427  \\ \hline
5 & -1.1329 \\ \hline
6  & -1.0075 \\ \hline
7 & -1.0001 \\ \hline
\end{tabular}
\end{table}
\end{document}

enter image description here

Following the tradition of the site, vertical lines are evil and a table that uses booktabs is neat, here is a booktabs version:

\documentclass{article}
\usepackage{amsmath,array,ragged2e,booktabs}
\newcolumntype{C}{>{\Centering\arraybackslash}m{0.17\linewidth}}
\begin{document}
\begin{table}
\centering
\begin{tabular}[t]{CcCcCc}
\toprule
\multicolumn{2}{c}{Table1} & \multicolumn{2}{c}{table2} & \multicolumn{2}{c}{table3}  \\ \midrule
A very long equation with k as input & Answer & A very long equation with k as input & Answer & A very long equation with k as input & Answer  \\ \cmidrule(lr){1-2}\cmidrule(lr){3-4}\cmidrule(lr){5-6}
1 & -19.0123 &  1 & -16.0123 & 1 & -5.0123  \\
2 & -16.4377 &  2 & -12.4377 & 2 & -2.4377 \\
3 & -13.3349 &  3 & -9.5532  & 3 & -3.3349 \\
4 & -11.7427 &  4 & -5.7427  & 4 & -1.7427  \\
5 & -10.1329 &  5 & -4.1329  & 5 & -1.1329 \\
6 & -9.0075  &  6 & -3.0075  & 6 & -1.0075 \\
7 & -6.0001  &  7 & -3.0001  & 7 & -1.0001 \\\bottomrule
\end{tabular}
\end{table}
\end{document}

enter image description here

In the above tables, the number should have been in math mode (see the minus sign). To do that you can define another new column like

\newcolumntype{P}{>{$}c<{$}}

and use it as 

\begin{tabular}[t]{CPCPCP}

Or.... use siunitx and its S column type:

\documentclass{article}
\usepackage{amsmath,array,ragged2e,booktabs,siunitx}
\newcolumntype{C}{>{\Centering\arraybackslash}m{0.17\linewidth}}
\newcolumntype{P}{S[table-format=3.4]}
\newcommand{\mc}[1]{\multicolumn{1}{c}{#1}}
\begin{document}
\begin{table}
\centering
\begin{tabular}[t]{CPCPCP}
\toprule
\multicolumn{2}{c}{Table1} & \multicolumn{2}{c}{table2} & \multicolumn{2}{c}{table3}  \\ \midrule
A very long equation with k as input & \mc{Answer} & A very long equation with k as input & \mc{Answer} & A very long equation with k as input & \mc{Answer}  \\ \cmidrule(lr){1-2}\cmidrule(lr){3-4}\cmidrule(lr){5-6}
1 & -19.0123 &  1 & -16.0123 & 1 & -5.0123  \\
2 & -16.4377 &  2 & -12.4377 & 2 & -2.4377 \\
3 & -13.3349 &  3 & -9.5532  & 3 & -3.3349 \\
4 & -11.7427 &  4 & -5.7427  & 4 & -1.7427  \\
5 & -10.1329 &  5 & -4.1329  & 5 & -1.1329 \\
6 & -9.0075  &  6 & -3.0075  & 6 & -1.0075 \\
7 & -6.0001  &  7 & -3.0001  & 7 & -1.0001 \\\bottomrule
\end{tabular}
\end{table}
\end{document}

enter image description here

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