# How to create a table with fixed column widths

I've put in the following code:

\begin{tabular} {l{4cm} l{5cm}}
hello & foo\\
hello & bar\\
\end{tabular}


and it gives me an error:

! LaTeX Error: Illegal character in array arg.

See the LaTeX manual or LaTeX Companion for explanation. Type H for immediate help. ...

                                               l.199 \begin{tabular} {l{4cm} l{5cm}}


Why doesn't it work? I'm trying to make a table with left justified text with fixed cell widths. If I just specify {l l} it works, but with the widths it gives me that error.

• Use p{4cm}p{5cm} not l{4cm}... It will be left aligned still then, but text will wrap around too. Please note that the width of the table is slightly larger than 9cm then – user31729 Jan 10 '16 at 15:43
• Have you seen any documentation that suggests l{4cm} should work? If you provide a link to it we could try to get it fixed. – David Carlisle Jan 10 '16 at 15:50
• @DavidCarlisle sharelatex.com/learn/Tables says m{5em}. It doesn't say what m does but I wanted my text left aligned. Anyway, it didn't work even with m instead of l. – CaptainCodeman Jan 10 '16 at 16:04
• m is vertical mid alignment and requires the array package. – David Carlisle Jan 10 '16 at 16:55

The standard column types are l, c, r and p which stands for left aligned, centered or right alignment and parbox.

Only the p - type can have a width argument, i.e. p{somewidth}, where width can be specified with any dimension TeX/LaTeX knows of.

The p - type is effectively \parbox which allows wrapping of text and content, which isn't possible (directly) in a l etc. type, for example an itemize or enumerate list.

The array package provides for example for the m type which is meant for vertical ('middle') aligned. In addition to this, array has the \newcolumntype macro which allows to define other column types, however, based on the existing 'base' types, i.e. r, l, c or p.

The tabularx package provides for the X columntype and the siunitx enables to use the S columntype.

Here's a small sample code for showing the width effects:

\begin{tabular}{|p{4cm}|p{6cm}|} will provide a tabular, that has the width of 4cm + 5cm + 4\tabcolsep + 3\arrayrulewidth, since each column has a left and right \tabcolsep space, the later defaulting to 6pt; and there are three |, so 3\arrayrulewidth lengths are added.

In total, even p{4cm}p{5cm} will be wider than the expected 9cm.

\documentclass{article}

\begin{document}

\begin{tabular}{|p{4cm}|p{5cm}|}
\hline
foo & bar
\end{tabular}

\begin{tabular}{|@{}p{4cm}@{}|@{}p{5cm}@{}|}
\hline
foo & bar
\end{tabular}

{%
\renewcommand{\arrayrulewidth}{0pt}%
\begin{tabular}{@{}p{4cm}@{}@{}p{5cm}@{}}
foo & bar
\end{tabular}
}

\end{document}


This workaround in the preamble solves the problem. You can simply use C{width} for centered entries. Replace C with L or R if raggedright or raggedleft is favoured.

\usepackage{array}
\newcommand{\PreserveBackslash}[1]{\let\temp=\\#1\let\\=\temp}
\newcolumntype{C}[1]{>{\PreserveBackslash\centering}p{#1}}
\newcolumntype{R}[1]{>{\PreserveBackslash\raggedleft}p{#1}}
\newcolumntype{L}[1]{>{\PreserveBackslash\raggedright}p{#1}}