I'm trying to make a longtable and use some R tools for generating them. The problem is that when a long table has more than one columns, it creates double headers, as shown here: https://stackoverflow.com/questions/20552459/excessive-elements-in-latex-longtable-output-when-more-than-one-row-is-used-in-h. I use LyX to generate the output.

This is one-column code:

\begin{document}

\setlongtables

\begin{longtable}{r}\caption{Title} \tabularnewline
\hline\hline
\multicolumn{1}{c}{X1.10}\tabularnewline
\hline
\hline
\multicolumn{1}{c}{X1.10}\tabularnewline
\hline
\hline
\endfoot
\label{data.frame}
$1$\tabularnewline
$2$\tabularnewline
$3$\tabularnewline
$4$\tabularnewline
$5$\tabularnewline
$6$\tabularnewline
$7$\tabularnewline
$8$\tabularnewline
$9$\tabularnewline
$10$\tabularnewline
\hline
\end{longtable}

\end{document}


And this is a two-column table:

\begin{document}

\setlongtables

\begin{longtable}{rr}\caption{Title} \tabularnewline
\hline\hline
\multicolumn{1}{c}{X1.10}&\multicolumn{1}{c}{X10.1}\tabularnewline
\hline
\hline
\multicolumn{1}{c}{X1.10}&\multicolumn{1}{c}{X10.1}\tabularnewline
\hline
\hline
\endfoot
\label{data.frame}
$1$&$10$\tabularnewline
$2$&$9$\tabularnewline
$3$&$8$\tabularnewline
$4$&$7$\tabularnewline
$5$&$6$\tabularnewline
$6$&$5$\tabularnewline
$7$&$4$\tabularnewline
$8$&$3$\tabularnewline
$9$&$2$\tabularnewline
$10$&$1$\tabularnewline
\hline
\end{longtable}

\end{document}


What's wrong with the latter one? Judging from the code, they are identical.

UPDATE

That was LyX: when my .tex file was imported in LyX, it created additional code (the header), so that further processing went wrong.

• Should the two posts be merged? – azetina Dec 14 '13 at 20:36

Please always post complete documents that show the problem. I had to guess to complete your fragment but I only get one heading, so presumably the problem is in the code you didn't show.

\documentclass{article}
\usepackage{longtable}
\begin{document}

\setlongtables

\begin{longtable}{rr}\caption{Title} \tabularnewline
\hline\hline
\multicolumn{1}{c}{X1.10}&\multicolumn{1}{c}{X10.1}\tabularnewline
\hline
\hline
\multicolumn{1}{c}{X1.10}&\multicolumn{1}{c}{X10.1}\tabularnewline
\hline
\hline
\endfoot
\label{data.frame}
$1$&$10$\tabularnewline
$2$&$9$\tabularnewline
$3$&$8$\tabularnewline
$4$&$7$\tabularnewline
$5$&$6$\tabularnewline
$6$&$5$\tabularnewline
$7$&$4$\tabularnewline
$8$&$3$\tabularnewline
$9$&$2$\tabularnewline
$10$&$1$\tabularnewline
\hline
\end{longtable}

\end{document}

• Thank you, David. I actually found the mistake. It was my file processing via LyX that added another row. Thanks to you I've checked it properly. – Anton Tarasenko Dec 14 '13 at 21:58
• @Anton do you want to close the question if it was a simple error , or if there is some general advice worth giving you could give a self answer (better an answer than adding it to the question) – David Carlisle Dec 14 '13 at 22:06

The problem occurred because I did conversion from .tex to .lyx before rendering a PDF file. At this stage, LyX tried to convert longtable (not a part of its native capacities) into a double simple table and added the double header.