Last column in table under \multicolumn is of different width

Question

I am struggling trying to have the four column under the multicolumn of same width and centered. This is the code:

\begin{table*}[ht]
    \centering
    \begin{tabular}{c|cccc|cc}
    \toprule
            \multirow{2}{*}{Model} & \multicolumn{4}{c|}{Percentage of predictions with error value}  &   \multirow{2}{*}{$\mu$} &   \multirow{2}{*}{$\sigma$} \\
               &   $<10\%$ &   $<5\%$  &   $<2\%$  &   $<1\%$\\
    \midrule
        Omega-Csi     &   100    &   99.95  &   98.52   &   95.77   &   -0.034  &   0.48\\
        9-Input, grid training   &   99.95    &   99.53  &   96.25   &   89.13   &   0.016  &   0.92\\
        9-Input, random training  &   100    &   99.94  &   99.51   &   97.98   &   -0.031  &   0.36\\
    \bottomrule
    \end{tabular}
    \caption{Percentage error characteristics of different model predictions on internal test sets}
    \label{tab:2}
\end{table*}

that generates this table:

\setlength\tabcolsep{width} doesn't work as it modifies the width of all columns and makes the table exceed the textwidth before equalizing the spaces. I would like to have all the column with the <% values of same width and occupying exactly the space under the \multicolumn header.

You might try to make the content of \multicolumn{4} use two lines with the makecell package. — Bernard, Jul 05 '22 at 10:10

Zarko · Accepted Answer · 2022-07-05T14:40:06.973

sum of widths of the columns spanned by \multicolumn cell should be greater than width of \multicolumn content. if it is not, than last spanned column is widened accordingly
solution (at "classic" tables) is prescribe appropriate width of spanned columns (below in the first table), or
for table use tabularray package (version 2022B) with option hspan=even which take a care that spanned columns have equal widths (second table below)
In the second table is also used S columns defined in siunitx packages (in example loaded as tabularray library) which enable align numbers at decimal points and use math ˙-˙symbol:

\documentclass[twocolumn]{article}
\usepackage[skip=1ex, font=small, labelfont=bf]{caption}
\usepackage{multirow, tabularx}
\usepackage{tabularray}
\UseTblrLibrary{booktabs, siunitx}
\begin{document}
\begin{table}
\centering
\begin{tabular}{l | {4}{>{\centering\arraybackslash} p{4em}} | cc}
    \toprule
\multirow{2}{}{Model} 
        & \multicolumn{4}{c|}{Percentage of predictions with error value}

                &   \multirow{2}{}{$\mu$} &   \multirow{2}{}{$\sigma$} \
        & $<10%$ & $<5%$  & $<2%$ & $<1%$                           &           &       \
    \midrule
Omega-Csi                &   100    &   99.95  &   98.52   &   95.77    & -0.034    & 0.48  \
9-Input, grid training   &   99.95  &   99.53  &   96.25   &   89.13    &  0.016    & 0.92  \
9-Input, random training &   100    &   99.94  &   99.51   &   97.98    & -0.031    & 0.36  \
    \bottomrule
    \end{tabular}
\caption{Percentage error characteristics of different model predictions on internal test sets}
    \label{tab:2}
\end{table}
\begin{table}
\caption{Percentage error characteristics of different model predictions on internal test sets}
\centering
\begin{tblr}{colspec = {l |      Q[c, si={table-format=3.2}]
                            {3}{Q[c, si={table-format=2.2}]}
                          |      Q[c, si={table-format=-1.3}]
                                 Q[c, si={table-format=1.2}] },
             hspan  = even,
             row{1} = {guard}
             }
    \toprule
\SetCell[r=2]{c} Model
    &   \SetCell[c=4]{c} Percentage of predictions with error value
        &   &   &   &   \SetCell[r=2]{c,$} \mu
                        &   \SetCell[r=2]{c,$}    \sigma    \
    & \qty{<10}{%} 
                &  \qty{<5}{%}

                        & \qty{<2}{%}

                                &  \qty{<1}{%}

                                        &           &       \
    \midrule
Omega-Csi
    & 100       & 99.95 & 98.52 & 95.77 & -0.034    & 0.48  \
9-Input, grid training
    &  99.95    & 99.53 & 96.25 & 89.13 &  0.016    & 0.92  \
9-Input, random training
    & 100       & 99.94 & 99.51 & 97.98 & -0.031    &  0.36 \
    \bottomrule
\end{tblr}
\end{table*}
\end{document}

Note: Since in code fragment you use table* float environment, I assume that document is of two columns.

Edit: ups, forgot to add image of tables :-(. Now is presented:

First solution worked great. It is also very similar to the one I referenced in the other answer, but that uses tabularx instead — mcali, Jul 06 '22 at 09:47
@mcali, both solution works. I prefer with tabularray because it simplicity (not need to calculate necessary spanned column widths) — Zarko, Jul 06 '22 at 10:06

score 0 · Answer 2 · answered Jul 05 '22 at 10:09

0

Found another post that helped me to fix the issue. It also has lots of other options for formatting differently: Table column widths disproportionate due to multicolumn cell being too long

answered Jul 05 '22 at 10:09

mcali

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Last column in table under \multicolumn is of different width

2 Answers2