How to add an additional spacing between two rows in longtable?

Question

I have a strange behaviour regarding longtable and array packages: When including the array package, I can no longer change the row spacing using \\[...] syntax. MWE:

\documentclass[a4paper,11pt]{scrartcl}
\usepackage{longtable}
% \usepackage{array} % Uncomment to trigger problem
\usepackage{lipsum}
\begin{document}
\begin{longtable}{ p{3cm} | %>{\raggedright\let\newline\\\arraybackslash}
p{10cm} }
a & b\\
c & \lipsum[1] \\[4cm]
d & e
\end{longtable}
\end{document}

(Remark: I want the right column to be left aligned instead of block text. Thus I wanted to use the array package.) Somehow it seems that LaTeX interprets the 4cm in the MWE differently if array is included or not:

• Without array there is 4cm spacing between row 2 and 3. This is my intention.
• With array included it seems that the 4cm are interpreted as something like the minimal height of a row. Enlarge it sufficiently and change the amount of text. In my compiled PDFs the third row is always on the same position or pushed down if the text is too much.

Can you confirm this behaviour? What can I do to avoid this?

Answer 1

Even without array it doesn't work as you expect. The space depends on in which column the long text is:

\documentclass[a4paper,11pt]{scrartcl}
\usepackage{longtable}
% \usepackage{array} % Uncomment to trigger problem
\usepackage{lipsum}
\begin{document}
\begin{longtable}{ p{10cm} | p{10cm} }
c &\lipsum[1] \\[4cm]
xxxxxxxxxx & xxxxxxxxxxx\\
\lipsum[1] &  c\\[4cm]
xxxxxxxxxx & xxxxxxxxxxx
\end{longtable}
\end{document}

With the newest version of array both case will give the same result and lead to a "minimum height".

If you really want a space imho the easiest is to insert an additional line:

  c &\lipsum[1] \\ \\[4cm]

An alternative is an invisible rule at the end of the long text.