Cdtrjyty

I have a minimal LaTeX document like this:

documentclass{article}

usepackage{tabularx}

begin{document}

  noindent

  begin{tabularx}{linewidth}{ X | X }

    centering A & B \ hline

    1.0 & 2.0 \

  end{tabularx}

end{document}

I would like to center the table headers but left-align the columns. However, when I add centering to the B header, like this:

documentclass{article}

usepackage{tabularx}

begin{document}

  noindent

  begin{tabularx}{linewidth}{ X | X }

    centering A & centering B \ hline

    1.0 & 2.0 \

  end{tabularx}

end{document}

I get this error:

! Misplaced noalign.

hline ->noalign

                  {ifnum 0=`}fi hrule @height arrayrulewidth futurelet...

l.8   end{tabularx}



! Extra alignment tab has been changed to cr.

<recently read> endtemplate



l.8   end{tabularx}



! Misplaced noalign.

hline ->noalign

                  {ifnum 0=`}fi hrule @height arrayrulewidth futurelet...

l.8   end{tabularx}



! Extra alignment tab has been changed to cr.

<recently read> endtemplate



l.8   end{tabularx}



! Misplaced noalign.

hline ->noalign

                  {ifnum 0=`}fi hrule @height arrayrulewidth futurelet...

l.8   end{tabularx}



! Extra alignment tab has been changed to cr.

<recently read> endtemplate



l.8   end{tabularx}

Page 2 of the tabularx documentation says that you have to use arraybackslash after centering (or raggedright or ragggedleft). Use like this:

documentclass{article}

usepackage{tabularx}

begin{document}

  noindent

  begin{tabularx}{linewidth}{ X | X }

    centeringarraybackslash A & centeringarraybackslash B \ hline

    1.0 & 2.0 \

  end{tabularx}

end{document}

LaTeX's text alignment commands redefine \ so that they don't mean “a new line in the table” anymore. The arraybackslash command does let\tabularnewline so that it will work again.

You can simply use a multicolumn{1}{c}{...} for the column heads. Or load makecell and use its thead command (by default, its content is centred, both horizontally and vertically), which has the possibility to define a common formatting of all theads arguments. Here is an example of both methods:

documentclass{article}

usepackage{tabularx, makecell, xcolor}

renewcommand{theadfont}{normalsizebfseriescolor{red}}



begin{document}



  noindent

  begin{tabularx}{linewidth}{ X | X }

    multicolumn{1}{c}{A} & multicolumn{1}{c}{B} \ hline

    1.0 & 2.0 \

  end{tabularx}

vspace{4ex}



  noindent

  begin{tabularx}{linewidth}{ X | X }

    thead{A} & thead{B} \ hline

    1.0 & 2.0 \

  end{tabularx}



end{document}