Tabularray – Column Alignment with Tabularray

formattingsiunitxtabularray

I'm trying center specific cells with tabularray, but I don't see how to override the alignment from siunitx. I want the cells on the second row from the top to be centered, but they are currently aligned at the decimal point.

\documentclass{standalone}
\usepackage{siunitx}
\usepackage{tabularray}
\usepackage{amsmath}
\UseTblrLibrary{booktabs,siunitx,amsmath}

\newcommand{\deltav}[1]{\ensuremath{\Delta V#1}}
\newcommand{\unitE}{\ensuremath{\text{km}^{2}/\text{s}^{2}}}
\providecommand\degrees[1]{\ensuremath{#1^\circ}} % for degrees symbol
\providecommand{\ccc}{\ensuremath{\text{C3}}}
\providecommand{\rla}{\ensuremath{\text{RLA}}}
\providecommand{\dla}{\ensuremath{\text{DLA}}}

\NewColumnType{H}[2]{S[table-format=#1, round-mode=places, round-precision = #2, scientific-notation = true, exponent-mode = fixed, fixed-exponent = 0]}
\NewColumnType{K}{H{6.4f}{4}}

\begin{document}
\begin{booktabs}{
    colspec = {c K K K},
    row{1} = {font=\bfseries},
    cell{1-2}{1-4} = {}{c},
  }
  \toprule
                         & \ccc                  & \rla                   & \dla                   \\
  Shift                  & 0.025\, \unitE{}      & 0.005\degrees{}        & 0.008\degrees{}        \\
  \midrule
  B.T km                 & 14028.09419155        & 982.72457669           & -13477.32067085        \\
  B.R km                 & -7751.49915236        & -3700.77434474         & 3148.12003385          \\
  \midrule
  \deltav{_\text{x}} m/s & 4.774015816660711e-01 & 4.126455467703491e-02  & -4.480105352801190e-01 \\
  \deltav{_\text{y}} m/s & 6.781754913310237e-01 & -7.925658411887511e-02 & -8.241304954028742e-01 \\
  \deltav{_\text{z}} m/s & 7.649481111877549e-01 & 4.826834479224431e-01  & -1.507332008655069e-01 \\
  \midrule
  \deltav{} m/s          & 1.128264100301457     & 4.908845897939598e-01  & 9.500657929944257e-01  \\
  \midrule
  TCM \deltav{} m/s      & 4.546833189860270e-0  & 4.563499345528536e-0   & 4.486347115134618e-0   \\
  \bottomrule
\end{booktabs}
\end{document}

which gives me

table of numbers and the cells in the second row are not centered

The most obvious misalignment is the cell containing "0.0250 km2/s2". I want that text centered in the column.

Best Answer

You should change booktabs preamble to:

    colspec = {c K K K},
    row{1} =  {c, font=\bfseries},
    row{2} =  {c, guard},  % <--- added `guard`

Explanation:
By adding guard to specification of the second row, this row not obey siunitx specifications for columns and text in cells in this row are just centered, i.e. after this addition you will get:

enter image description here

However, I would write your table on the following, to my opinion simpler and more in tabularray spirit, way where is considered @Mico comment too:

\documentclass[margin=3mm]{standalone}
\usepackage{tabularray}
\UseTblrLibrary{amsmath, booktabs, siunitx}

\begin{document}
    \begingroup
\sisetup{table-format=-5.4, 
         round-mode=places, round-precision = 4,
         }
\begin{booktabs}{
    colspec = {Q[c, mode=math] S S S},
    row{1} =  {c, font=\bfseries, guard},
    row{2} =  {c, guard, mode=text, cmd={\sisetup{round-precision=3}}},
                }
  \toprule
            & C3                        & RLA                      & DLA                    \\
Shift       & \qty{0.025}{\km^2/\s^2}   & \qty{0.005}{\degree}   & \qty{0.008}{\degree}   \\
\midrule
B.T km      & 14028.09419155            & 982.72457669           & -13477.32067085        \\
B.R km      & -7751.49915236            & -3700.77434474         & 3148.12003385          \\
\midrule
\Delta_{\mathrm{x}} m/s 
            & 4.774015816660711e-01     & 4.126455467703491e-02  & -4.480105352801190e-01 \\
\Delta_{\mathrm{y}} m/s 
            & 6.781754913310237e-01     & -7.925658411887511e-02 & -8.241304954028742e-01 \\
\Delta_{\mathrm{z}} m/s 
            & 7.649481111877549e-01     & 4.826834479224431e-01  & -1.507332008655069e-01 \\
\midrule
\Delta m/s            
            & 1.128264100301457         & 4.908845897939598e-01  & 9.500657929944257e-01  \\
\midrule
\mathrm{TCM}\;\Delta m/s       
            & 4.546833189860270e-0      & 4.563499345528536e-0   & 4.486347115134618e-0   \\
  \bottomrule
\end{booktabs}
    \endgroup
\end{document}
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