Tabular column with equal width

Question

I am trying make the width of the columns below Very very long name the same (G1 and G2). The one on the top is created by using tabular and the other one is created with tabularx. I have seen similar questions, but could not apply their solutions to my case.

\documentclass{article}

\usepackage{graphicx}
\usepackage{multirow}
\usepackage{tabularx}


\begin{document}

\begin{table}[ht]
    \centering
    \resizebox{\textwidth}{!}{
    \renewcommand{\arraystretch}{1.5} % Default value: 1
    \begin{tabular}{lcccccc}
            \multicolumn{7}{c}{\textbf{ABC Metrics}} \\ \hline
            \multicolumn{1}{|l|}{\textbf{Algorithm}} & \multicolumn{2}{c|}{\textit{Very very long name}} & \multicolumn{2}{c|}{\textit{Very very long name}} & \multicolumn{2}{c|}{\textit{Very very long name}} \\ \hline
            \multicolumn{1}{|l|}{\textbf{Graph}} & \multicolumn{1}{c|}{$G_1$} & \multicolumn{1}{c|}{$G_2$} & \multicolumn{1}{c|}{$G_1$} & \multicolumn{1}{c|}{$G_2$} & \multicolumn{1}{c|}{$G_1$} & \multicolumn{1}{c|}{$G_2$} \\ \hline
    \end{tabular}}
\end{table}


\begin{tabularx}{\textwidth}{XXXXXXX}
            \multicolumn{7}{c}{\textbf{ABC Metrics}} \\ \hline
            \multicolumn{1}{|l|}{\textbf{Algorithm}} & \multicolumn{2}{c|}{\textit{Very very long name}} & \multicolumn{2}{c|}{\textit{Very very long name}} & \multicolumn{2}{c|}{\textit{Very very long name}} \\ \hline
            \multicolumn{1}{|l|}{\textbf{Graph}} & \multicolumn{1}{c|}{$G_1$} & \multicolumn{1}{c|}{$G_2$} & \multicolumn{1}{c|}{$G_1$} & \multicolumn{1}{c|}{$G_2$} & \multicolumn{1}{c|}{$G_1$} & \multicolumn{1}{c|}{$G_2$} \\ \hline
\end{tabularx}

\end{document}

Answer 1

If you load geometry, you'll have more sensible margins. The default is designed for marginal notes, so if you don't use them, you'll have more space on the line.

Note you shouldn't use \resizebox with tables, as it leads to inconsistent font sizes. Finally I don't see what all those \multicolumn{1}{c|} are in the code for, since you can centre the content of an X cell?

Here is a code with X cells:

\documentclass{article}
\usepackage[showframe]{geometry}
\usepackage{graphicx}
\usepackage{ragged2e}
\usepackage{tabularx}

\begin{document}

\begin{table}[!ht]
    \centering
    \renewcommand{\arraystretch}{1.5} % 
    \setlength{\tabcolsep}{4pt}
\begin{tabularx}{\textwidth}{|>{\hsize=1.72\hsize\bfseries\RaggedRight}X|*{6}{>{\centering\arraybackslash\hsize=0.88\hsize}X|}}
            \multicolumn{7}{c}{\textbf{ABC Metrics}} \\[1ex] \hline
            \textbf{Algorithm}& \multicolumn{2}{c|}{\textit{Very very long name}} & \multicolumn{2}{c|}{\textit{Very very long name}} & \multicolumn{2}{c|}{\textit{Very very long name}} \\
            \hline%
            \textbf{Graph} & $G₁$ & $G₂$ & $G₁$ & $G₂$ & $G₁$ & $G₂$ \\ 
            \hline%
            \textbf{Weighted Ortho\-gonal Ordering} & $G₁$ & $G₂$ & $G₁$ & $G₂$ & $G₁$ & $G₂$ \\ \hline
\end{tabularx}
\end{table}

\end{document}

Answer 2

A possible solution based on tabularx could be the following:

\documentclass{article}

\usepackage{ragged2e}
\usepackage{tabularx}
\newcolumntype{Y}{>{\Centering\arraybackslash}X}
\newcolumntype{Z}[1]{>{\Centering\arraybackslash\hsize=#1\hsize}X}

\begin{document}

\begin{tabularx}{\textwidth}{|l|Y|Y|Y|Y|Y|Y|}
  \multicolumn{7}{c}{\textbf{ABC Metrics}} \\ 
  \hline
  \textbf{Algorithm} & \multicolumn{2}{Z{2.3}|}{\textit{Very very long name}} & \multicolumn{2}{Z{2.3}|}{\textit{Very very long name}} & \multicolumn{2}{Z{2.3}|}{\textit{Very very long name}} \\ 
  \hline
  \textbf{Graph} & $G_1$  & $G_2$ & $G_1$ & $G_2$ & $G_1$ & $G_2$ \\ \hline
\end{tabularx}

\end{document}

In the above example, I have removed redundant \multicolumn commands. In order to horizontally center the contents of X columns, I have defined the new column type Y. For the multiolumns, I have replaced the c type columns by additionally defined Z type columns, that are based on X columns and therefor allow for automated linebreaks to make the table fit into the textwidth.

Answer 3

which table is more easy to read? the first? the second?

\documentclass{article}
\usepackage{tabularx}
\newcolumntype{C}{>{\centering\arraybackslash}X}
\newcommand\mcxit[1]{\multicolumn{2}{>{\hsize=\dimexpr2\hsize+2\tabcolsep}C|}{\textit{#1}}}

\begin{document}

\begin{table}[ht]
    \centering
    \tiny
    \renewcommand{\arraystretch}{1.2} % Default value: 1
\begin{tabularx}{\linewidth}{|>{\bfseries}l|*{6}{C|}}
\multicolumn{7}{c}{\textbf{ABC Metrics}} \\[1ex] \hline
Algorithm   & \mcxit{Weighted Orthogonal Ordering}
            & \mcxit{Weighted Orthogonal Ordering}
            & \mcxit{Weighted Orthogonal Ordering}       \\
    \hline%
Graph       & $G_1$ & $G_2$ & $G_1$ & $G_2$ & $G_1$ & $G_2$ \\ \hline
\end{tabularx}
\end{table}

\begin{table}[ht]
    \centering
    \renewcommand{\arraystretch}{1.2} % Default value: 1
\begin{tabularx}{\linewidth}{|>{\bfseries}l|*{6}{C|}}
\multicolumn{7}{c}{\textbf{ABC Metrics}} \\[1ex] \hline
Algorithm   & \mcxit{Weighted Orthogonal Ordering}
            & \mcxit{Weighted Orthogonal Ordering}
            & \mcxit{Weighted Orthogonal Ordering}       \\
    \hline%
Graph       & $G_1$ & $G_2$ & $G_1$ & $G_2$ & $G_1$ & $G_2$ \\ \hline
\end{tabularx}
\end{table}

\end{document}

in both cases, as you can see from mwe, are used your page layout (default for article). however, if you increase \textwidth with use of the package geometry, as suggested Bernard in his answer:

\documentclass{article}
\usepackage[margin=20mm]{geometry}
\usepackage{tabularx}
% follows the same code as in mwe above

the table looks far better:

from above table images follows, that the second one is reasonable compromise.

edit: one possible solution is to allow to table that it can spill-out from right text border. for example with use of the package changepage:

\documentclass{article}
\usepackage{changepage}
\usepackage{tabularx}
\newcolumntype{C}{>{\centering\arraybackslash}X}
\newcommand\mcxit[1]{\multicolumn{2}{>{\hsize=\dimexpr2\hsize+2\tabcolsep}C|}{\textit{#1}}}

%-------------------------------------- only for show page layout
\usepackage{showframe}
\renewcommand\ShowFrameLinethickness{0.25pt}
\renewcommand*\ShowFrameColor{\color{red}}
%---------------------------------------------------------------%

\begin{document}

\begin{table}[ht]
\begin{adjustwidth*}{0pt}{-\dimexpr\marginparsep+\marginparwidth}
    \small
    \renewcommand{\arraystretch}{1.2} % Default value: 1
\begin{tabularx}{\linewidth}{|>{\bfseries}l|*{6}{C|}}
\multicolumn{7}{c}{\textbf{ABC Metrics}} \\[1ex] \hline
Algorithm   & \mcxit{Weighted Orthogonal Ordering}
            & \mcxit{Weighted Orthogonal Ordering}
            & \mcxit{Weighted Orthogonal Ordering}       \\
    \hline%
Graph       & $G_1$ & $G_2$ & $G_1$ & $G_2$ & $G_1$ & $G_2$ \\ \hline
\end{tabularx}
\end{adjustwidth*}
\end{table}
\end{document}

which still result with column headers text in two lines:

(red lines indicate page layout).