As the lesson didn’t cover all the available preamble-tokens, a few others are
explained with examples here. You might want to revisit the tables at the start
of the lesson to get an overview of the things available. The short descriptions
provided there should suffice to understand what the different column types m,
b, w, and W do after you understood l, c, r, and p. If not you
might want to experiment a bit with them. What’s still missing are the handy
other preamble-tokens >, <, @, !, and |.
Since > and < can be used to put things before and after the cell contents
of a column, you can use these to add commands which affect the look
of a column. For instance, if you want to italicize the first column and put a
colon after it, you can do the following:
\documentclass{article}
\usepackage{array}
\usepackage{booktabs}
\begin{document}
\begin{tabular}{>{\itshape}l<{:} *{2}{l}}
\toprule
Animal & Food & Size \\
\midrule
dog & meat & medium \\
horse & hay & large \\
frog & flies & small \\
\bottomrule
\end{tabular}
\end{document}
\itshape makes all the following text italic, but its effect is ‘contained’
by the table cell. We will look at manual font formatting in a few lessons
time.
You may want the first cell not to be affected
because it is the table head. Here \multicolumn may be used. Remember that
it can be used to change a single cell’s alignment as shown below.
\documentclass{article}
\usepackage{array}
\usepackage{booktabs}
\begin{document}
\begin{tabular}{>{\itshape}l<{:} *{2}{l}}
\toprule
\multicolumn{1}{l}{Animal} & Food & Size \\
\midrule
dog & meat & medium \\
horse & hay & large \\
frog & flies & small \\
\bottomrule
\end{tabular}
\end{document}
Usually LaTeX pads each column by some space on both sides to give a balanced
look and separate them. This space is defined with the length \tabcolsep. Due
to the fact that each column is padded on both sides you get one \tabcolsep on
either end of the table, and 2\tabcolsep between two columns – one from
each column. You can adjust this space to any length using \setlength:
\documentclass{article}
\usepackage{array}
\setlength\tabcolsep{1cm}
\begin{document}
\begin{tabular}{lll}
Animal & Food & Size \\
dog & meat & medium \\
horse & hay & large \\
frog & flies & small \\
\end{tabular}
\end{document}
You can change this space to something arbitrary using @. This will remove the
padding between two columns or on either end, and instead put anything in
between the columns you specify as an argument:
\documentclass{article}
\usepackage{array}
\begin{document}
\begin{tabular}{l@{ : }l@{\hspace{2cm}}l}
Animal & Food & Size \\
dog & meat & medium \\
horse & hay & large \\
frog & flies & small \\
\end{tabular}
\end{document}
(We’ll see \hspace again shortly; you might guess that it adds a
horizontal space.)
The ! preamble token does something pretty similar. The difference is, that it
adds its argument in center of the space between two columns.
\documentclass{article}
\usepackage{array}
\begin{document}
\begin{tabular}{l!{:}ll}
Animal & Food & Size \\
dog & meat & medium \\
horse & hay & large \\
frog & flies & small \\
\end{tabular}
\end{document}
Sometimes you have to use vertical rules.
\documentclass{article}
\usepackage{array}
\begin{document}
\begin{tabular}{l|ll}
Animal & Food & Size \\[2pt]
dog & meat & medium \\
horse & hay & large \\
frog & flies & small \\
\end{tabular}
\end{document}
You might notice that the behavior of | is pretty similar to !{decl}; it
adds the vertical rule between two columns leaving the padding as it is. There
is a huge downside to this though; vertical rules don’t work with the
horizontal rules provided by booktabs. You can use the horizontal rules
provided by LaTeX; those are \hline (corresponding to \toprule, \midrule, and
\bottomrule) and \cline (which behaves like \cmidrule). As shown above, vertical rules
will span any space specified in the optional argument to \\.
booktabs rulesAll the booktabs rules and also \addlinespace support an optional argument
in brackets with which you can specify the rule’s thickness. In addition the
trimming provided by \cmidrule can be customized by specifying a length in
braces after r or l.
\documentclass{article}
\usepackage{array}
\usepackage{booktabs}
\begin{document}
\begin{tabular}{@{} lll@{}} \toprule[2pt]
Animal & Food & Size \\ \midrule[1pt]
dog & meat & medium \\
\cmidrule[0.5pt](r{1pt}l{1cm}){1-2}
horse & hay & large \\
frog & flies & small \\ \bottomrule[2pt]
\end{tabular}
\end{document}
The alignment of numbers in tables can be handled by the column type S
that is provided by the siunitx package.
A simple example with two aligned numeric columns would be:
\documentclass{article}
\usepackage{booktabs}
\usepackage{siunitx}
\begin{document}
\begin{tabular}{SS}
\toprule
{Values} & {More Values} \\
\midrule
1 & 2.3456 \\
1.2 & 34.2345 \\
-2.3 & 90.473 \\
40 & 5642.5 \\
5.3 & 1.2e3 \\
0.2 & 1e4 \\
\bottomrule
\end{tabular}
\end{document}
Note that any non-numeric cell must be “protected” by enclosing it in braces.
The siunitx package provides many possibilities for formatting the numbers in
different ways; see the package
documentation.
The width of a tabular environment is automatically determined based
on the contents of the table. There are two commonly used mechanisms
to specify a different total width.
Note that it is almost always preferable to format the table to a
specified width as below (perhaps using a font size such as \small if
necessary) rather than scaling a table with \resizebox and similar
commands which will produce inconsistent font sizes and rule widths.
tabular*The tabular* environment takes an additional width argument that
specifies the total width of the table. Stretchy space must be added
to the table using the \extracolsep command. This space is added
between all columns from that point in the preamble. It is almost
always used with \fill, a special space that stretches to be as large
as necessary.
\documentclass{article}
\usepackage{array}
\begin{document}
\begin{center}
\begin{tabular}{cc}
\hline
A & B\\
C & D\\
\hline
\end{tabular}
\end{center}
\begin{center}
\begin{tabular*}{.5\textwidth}{@{\extracolsep{\fill}}cc@{}}
\hline
A & B\\
C & D\\
\hline
\end{tabular*}
\end{center}
\begin{center}
\begin{tabular*}{\textwidth}{@{\extracolsep{\fill}}cc@{}}
\hline
A & B\\
C & D\\
\hline
\end{tabular*}
\end{center}
\end{document}
tabularxThe tabularx environment, provided by the package of
the same name, has a similar syntax to tabular* but instead of
adjusting the inter-column space, adjusts the widths of columns
specified by a new column type, X. This is equivalent to a
specification of p{...} for an automatically determined width.
\documentclass{article}
\usepackage{tabularx}
\begin{document}
\begin{center}
\begin{tabular}{lp{2cm}}
\hline
A & B B B B B B B B B B B B B B B B B B B B B B B B\\
C & D D D D D D D\\
\hline
\end{tabular}
\end{center}
\begin{center}
\begin{tabularx}{.5\textwidth}{lX}
\hline
A & B B B B B B B B B B B B B B B B B B B B B B B B\\
C & D D D D D D D\\
\hline
\end{tabularx}
\end{center}
\begin{center}
\begin{tabularx}{\textwidth}{lX}
\hline
A & B B B B B B B B B B B B B B B B B B B B B B B B\\
C & D D D D D D D\\
\hline
\end{tabularx}
\end{center}
\end{document}
Unlike the other forms discussed in these lessons, tabularx needs to
typeset the table several times with trial widths to determine the
final setting. This means that there are several restrictions on the
use of the environment; see the
package documentation.
A tabular forms an unbreakable box so it must be small enough to fit
on one page, and is often placed in a floating table environment.
Several packages provide variants with similar syntax that do allow
page breaking. Here we show the longtable package:
\documentclass{article}
\usepackage[paperheight=8cm,paperwidth=8cm]{geometry}
\usepackage{array}
\usepackage{longtable}
\begin{document}
\begin{longtable}{cc}
\multicolumn{2}{c}{A Long Table}\\
Left Side & Right Side\\
\hline
\endhead
\hline
\endfoot
aa & bb\\
Entry & b\\
a & b\\
a & b\\
a & b\\
a & b\\
a & bbb\\
a & b\\
a & b\\
a & b\\
a & b\\
a & b\\
a & b\\
a & b b b b b b\\
a & b b b b b\\
a & b b\\
A Wider Entry & b\\
\end{longtable}
\end{document}
longtable is notable in that it preserves the column widths
over all pages of the table; however in order to achieve this it
may take several runs of LaTeX so that wide entries encountered later
in the table can affect the column widths in earlier pages.
It is quite common to need footnote-like marks in a table referring to
notes under the table. The threeparttable package simplifies the
markup for such tables, arranging that the notes are set in a
block the same width as the table. Refer to the
package documentation
for full details, but we show a simple example here.
\documentclass{article}
\usepackage{array}
\usepackage{threeparttable}
\begin{document}
\begin{table}
\begin{threeparttable}
\caption{An Example}
\begin{tabular}{ll}
An entry & 42\tnote{1}\\
Another entry & 24\tnote{2}\\
\end{tabular}
\begin{tablenotes}
\item [1] the first note.
\item [2] the second note.
\end{tablenotes}
\end{threeparttable}
\end{table}
\end{document}
The default line breaking settings assume relatively long lines to
give some flexibility in choosing line breaks. The following example
shows some possible approaches. The first table shows interword spacing
stretched and TeX warns about Underfull lines. Using \raggedright
usually avoids this problem but may leave some lines ‘too ragged’. The
\RaggedRight command from the ragged2e package is a compromise;
it allows some raggedness in the line lengths, but will also
hyphenate where necessary, as shown in the third table.
Note the use of \arraybackslash here, which resets the definition of
\\ so that it ends the table row.
An alternative technique, as shown in the fourth table, is to use a smaller font so that the columns are not so narrow relative to the text size.
\documentclass[a4paper]{article}
\usepackage{array}
\usepackage{ragged2e}
\begin{document}
\begin{table}
\begin{tabular}[t]{lp{3cm}}
One & A long text set in a narrow paragraph, with some more example text.\\
Two & A different long text set in a narrow paragraph, with some more hard to hyphenate words.
\end{tabular}%
\begin{tabular}[t]{l>{\raggedright\arraybackslash}p{3cm}}
One & A long text set in a narrow paragraph, with some more example text.\\
Two & A different long text set in a narrow paragraph, with some more hard to hyphenate words.
\end{tabular}%
\begin{tabular}[t]{l>{\RaggedRight}p{3cm}}
One & A long text set in a narrow paragraph, with some more example text.\\
Two & A different long text set in a narrow paragraph, with some more hard to hyphenate words.
\end{tabular}
\footnotesize
\begin{tabular}[t]{lp{3cm}}
One & A long text set in a narrow paragraph, with some more example text.\\
Two & A different long text set in a narrow paragraph, with some more hard to hyphenate words.
\end{tabular}
\end{table}
\end{document}
As demonstrated in the main lesson, the array package allows
constructs such as >{\bfseries}c to denote a bold centered column.
It is often convenient to define a new column type to encapsulate such
use, for example
\newcolumntype{B}{>{\bfseries}c}
would allow the use of B in table preambles to specify a bold
centered column.
Often, rather than making a cell span multiple rows it is better to instead have
a single row in which some cells are split vertically by the use of nested
tabular environments.
\documentclass{article}
\usepackage{array}
\usepackage{booktabs}
\begin{document}
\begin{tabular}{lcc}
\toprule
Test & \begin{tabular}{@{}c@{}}A\\a\end{tabular} & \begin{tabular}{@{}c@{}}B\\b\end{tabular} \\
\midrule
Content & is & here \\
Content & is & here \\
Content & is & here \\
\bottomrule
\end{tabular}
\end{document}
Note that you can control vertical alignment by an optional argument to the
tabular; it supports the usage of t, c, or b for top, centered, or
bottom aligned respectively and is used like this:
\documentclass{article}
\usepackage{array}
\usepackage{booktabs}
\begin{document}
\begin{tabular}{lcc}
\toprule
Test & \begin{tabular}[b]{@{}c@{}}A\\a\end{tabular} & \begin{tabular}[t]{@{}c@{}}B\\b\end{tabular} \\
\midrule
Content & is & here \\
Content & is & here \\
Content & is & here \\
\bottomrule
\end{tabular}
\end{document}
In the main lesson we demonstrated \addlinespace from the booktabs
package, which is useful for adding extra space between specific lines.
There are two general parameters that control line spacing,
\arraystretch and \extrarowheight (the latter from the array
package).
\renewcommand\arraystretch{1.5}
will increase the baseline spacing by 50%.
Often, especially when using \hline, it is better just to increase
the height of rows, without increasing their depth below the baseline.
The following example demonstrates the \extrarowheight parameter.
\documentclass[a4paper]{article}
\usepackage{array}
\begin{document}
\begin{center}
\begin{tabular}{cc}
\hline
Square& $x^2$\\
\hline
Cube& $x^3$\\
\hline
\end{tabular}
\end{center}
\begin{center}
\setlength\extrarowheight{2pt}
\begin{tabular}{cc}
\hline
Square& $x^2$\\
\hline
Cube& $x^3$\\
\hline
\end{tabular}
\end{center}
\end{document}