different spacing in whiledo with tabular

Question

Sometimes, I observe different spaces introduced when I use whiledo in a tabular environment. How can I get rid of them?

Check the following MWE:

\documentclass{article}
\usepackage{ifthen}
\newcounter{qai}
\def\myand{&}
\begin{document}
\begin{tabular}{ |l|l|l|l|} \hline
    Q & Q & Q & Q\  \hline
    \setcounter{qai}{1}
    \whiledo{\value{qai}<3}{Q\myand\stepcounter{qai}} 
    Q & Q \\hline
\end{tabular}
\end{document}

Note that the cells are not aligned.

score 5 · Accepted Answer · answered Oct 15 '22 at 20:21

You are adding space from ends of line:

\documentclass{article}
\usepackage{ifthen}
\newcounter{qai}
\def\myand{&}
\begin{document}
\begin{tabular}{ |l|l|l|l|} \hline
    Q & Q & Q & Q\  \hline
    \setcounter{qai}{1}%
    \whiledo{\value{qai}<3}{Q\myand\stepcounter{qai}}%
    Q & Q \\hline
\end{tabular}
\end{document}

score 5 · Answer 2 · answered Oct 15 '22 at 20:33

As David points out, there are spaces you don't take into account.

There are far better ways to do repetitive tasks than \whiledo.

\documentclass{article}
\ExplSyntaxOn
\NewExpandableDocumentCommand{\Repeat}{m O{} +m}
 {% #1 = number of repetitions
  % #2 = what to put in between
  % #3 = thing to repeat
  \int_compare:nT { #1 > 0 }
   {% do nothing if #3 <= 0
    #3
    \prg_replicate:nn { #1 - 1 } { #2 #3 }
   }
 }
\ExplSyntaxOff
\begin{document}
\Repeat{10}{I must not drive the principal's car\par}
\bigskip
\begin{tabular}{|c|c|c|c|}
  \hline
  Q & Q & Q & Q \
  \hline
  \Repeat{4}[&]{Q} \
  \hline
\end{tabular}
\end{document}

different spacing in whiledo with tabular

2 Answers2