# booktabs and tiny horizontal space

In a regular table, I'm trying to remove the small horizontal space before the first column and after the last one as achieved with package booktabs with the option @{}. How can I do that? Please compile the code below:

\documentclass[fleqn,11pt]{book}
\usepackage{booktabs}
\begin{document}
\begin{table}[!ht]\centering
\begin{tabular}{@{}llr@{}} \toprule
Gnat & per gram & 13.65 \\
Gnu & stuffed & 92.50 \\ \bottomrule
\end{tabular}
\end{table}
\begin{table}[!ht]\centering
\begin{tabular}{llr} \toprule
Gnat & per gram & 13.65 \\
Gnu & stuffed & 92.50 \\ \bottomrule
\end{tabular}
\end{table}
\end{document}

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The @{} specification in tabular works with any table; it's not specific to booktabs. –  Alan Munn Oct 27 '11 at 3:20
too bad! I tried few minutes ago and I did not notice it worked. Thanks. I see why I missed it. Option @{} has no effect on colored rows –  pluton Oct 27 '11 at 3:22

The @{} specification in tabular works with any table. It's not specific to the booktabs package.

Here's an example with \fboxes around the table to show the boundaries.

\documentclass{article}
\begin{document}

\fbox{\begin{tabular}{ll}
foo & bar\\
bar & foo
\end{tabular}}

\fbox{\begin{tabular}{@{}ll@{}}
foo & bar\\
bar & foo
\end{tabular}}

\end{document}


-

The colortbl commands \columncolor and \rowcolor add a overhang to the colored cells in order to connect them; the default value of the overhang is \tabcolsep; if you color by columns you can specify the left and right overhangs as optional arguments to \columncolor; for \rowcolor it's more difficult, as the same overhang is used for all cells in a row:

\setlength{\tabcolsep}{1pt}
\begin{tabular}{l<{\hspace{2pt}}
>{\hspace{2pt}}l<{\hspace{2pt}}
>{\hspace{2pt}}r}
\toprule
\rowcolor{green}
Gnat & per gram & 13.65 \\
\rowcolor{blue}
Gnu & stuffed & 92.50 \\
\bottomrule
\end{tabular}


In other words, you emulate the \tabcolsep space between columns by inserting space manually. With colored rows I would stick to the normal \tabcolsep space also before and after the table.

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the colortbl package offers an option to control horizontal space for row coloring as follows: \rowcolor{blue!5}[0pt][0pt]. By adding an extra empty column in the middle I could achieve what I wanted, i.e. \begin{table} \begin{tabular}{@{}r@{}r@{}p{5cm}@{}} \hline \rowcolor{blue!5}[0pt][0mm]0&\hphantom{0}& text \\ 10&& text \\\hline\end{tabular}\end{table} –  pluton Oct 27 '11 at 12:34
@pluton The cell won't be connected, with this setting, unless you set also \tabcolsep to 0pt; with the trick there will still be a small overhang that's necessary with l or r columns and the widest entry in c columns. –  egreg Oct 27 '11 at 12:39