[Tex/LaTex] How to center all tables in a document

floatshorizontal alignmentlyxtables

Background

Would like to center all tables within floats, without having to add \centering to each table.

Ideas

Tried the following:

\let\originaltabular\tabular
\renewcommand\tabular{\centering\originaltabular}

It compiles, but the tables remain left-justified.

Question

How would you edit the Preamble of a LyX document to make all the floating tables be centred?

Best Answer

If you would like to center all tabular environments, I would recommend to create your own environment with a different name, which calls tabular. You could use that instead of redefining tabular itself.

But no problem, this can be done. Just use \renewenvironment, for example:

\let\originaltabular\tabular
\let\endoriginaltabular\endtabular
\renewenvironment{tabular}[1]{%
  \begingroup%
  \centering%
  \originaltabular{#1}}%
  {\endoriginaltabular\endgroup}

This as addition to your first try redefining tabular.

You could redefine the floating table environment very similar:

\let\originaltable\table
\let\endoriginaltable\endtable
\renewenvironment{table}[1][ht]{%
  \originaltable[#1]
  \centering}%
  {\endoriginaltable}

You could also use etoolbox to patch the table environment or append \centering to the definition this way:

\makeatletter
\g@addto@macro{\table}{\centering}
\makeatother

\expandafter\def\expandafter\table\expandafter{\table\centering}

Related Solutions

[Tex/LaTex] Override \centering to left justify an image

This is untested, but how about something like the following?

\expandafter\def\expandafter\algorithm\expandafter{%
        \expandafter\let\expandafter\centering\expandafter\relax
        \algorithm
}

This makes \centering do nothing in the algorithm environment. (There's actually a better way to do such things with the etoolbox package.) If you want, you could replace \relax with \raggedright (or better \RaggedRight from the ragged2e package) if you really want that behavior. The flushleft environment is not what you want since that's going to add extra space.

Edit:
Actually, I've got a better idea than redefining \centering locally which just feels wrong. How about this:

\let\oldincludegraphics\includegraphics[2][]{%
        \oldincludegraphics[width=\ScaleIfNeeded]{#2}%
        \graphicsalignment
}
\expandafter\def\expandafter\algorithm\expandafter{%
        \expandafter\let\expandafter\graphicsalignment\expandafter\relax
        \algorithm
}
\let\graphicsalignment\centering

Bonus Question:
Here's one idea for getting a rule.

\newdimen\coderulewidth \coderulewidth=1em
\newdimen\coderulesep \coderulesep=1em
\newdimen\coderuleseptemp
\newbox\codebox
\newenvironment{coderule}[1][\coderulesep]{%
        \par
        \coderuleseptemp=#1\relax
        \setbox\codebox=\vbox\bgroup
                \linewidth=\dimexpr\linewidth-\coderulewidth-\coderulesep\relax
                \hsize=\linewidth
}{%
        \egroup
        \noindent
        \strut
        \hbox{%
                \vrule width\coderulewidth
                \kern\coderuleseptemp
                \box\codebox
        }%
}

As an example of usage, here are a few grafs with the thick rule on the left (this example needs the lipsum package).

\begin{coderule}
\lipsum[1-2]
\end{coderule}

For an algorithmic, the algorithm is already indented, so you can use the optional argument (or just redefine \coderulesep).

\begin{algorithm}
\begin{coderule}[0pt]
\begin{algorithmic}
\STATE $x\gets0$
\STATE $y\gets1$
\STATE $z\gets x+y$
\end{algorithmic}
\end{coderule}
\end{algorithm}

[Tex/LaTex] How to left-align a table in LaTeX

\let\centering\relax in the preamble will cancel \centering everywhere, or to be more selective and only cancel in floats, you can try

\makeatletter
\let\old@float\@float
\def\@float{\let\centering\relax\old@float}
\makeatother

You will still need to edit the \floatsetup{} line as lockstep described.