pgfplotstable multiple columns same heading name

Question

I have some x y data that I wish to typeset using pgfplotstable, rather than having say 9 rows of 2 columns, I would like to have 3 rows, with 3 sets of xy pairs.

Consider the following:

\documentclass{article}
\usepackage{pgfplotstable,filecontents}

\begin{filecontents}{mydata.dat}
    x y x y x y
    0 0 3 3 6 6
    1 1 4 4 7 7
    2 2 5 5 8 8
\end{filecontents}

\begin{document}
    \pgfplotstableset{
        columns/x/.style={
             column name={$X$},
        },
        columns/y/.style={
              column name={$Y$},
              column type/.add={}{|}
        },
    }
    \pgfplotstableread{mydata.dat}\loadedtable
    \pgfplotstabletypeset{\loadedtable}
\end{document}

Which produces the following output:

Clearly columns 2 to 6, in this MWE are not being typeset as desired. I am aware that this can be resolved by declaring unique column style for each column as follows:

\pgfplotstableset{
  columns/A/.style={
    column name={$X$},
  },
  columns/B/.style={
    column name={$Y$},
    column type/.add={}{|}
  },
  columns/C/.style={
   column name={$X$},
  },
  columns/D/.style={
    column name={$Y$},
    column type/.add={}{|}
  },
  columns/E/.style={
    column name={$X$},
  },
  columns/F/.style={
    column name={$Y$},
    column type/.add={}{|}
  },
}

Also slightly modifying the input data structure:

\begin{filecontents}{mydata.dat}
    A B C D E F
    0 0 3 3 6 6
    1 1 4 4 7 7
    2 2 5 5 8 8
\end{filecontents}

Producing the desired format, with column names [X Y X Y X Y]:

But I am trying to avoid having to effectively re-type the same code over and over. How can I use the same pgfplotstableset column style, for multiple columns in the same table.

Answer 1

You can use the every odd column and every even column styles for this (noting that the column numbering starts at zero):

\documentclass{article}
\usepackage{pgfplotstable,filecontents}

\begin{filecontents}{mydata.dat}
    x y x y x y
    0 0 3 3 6 6
    1 1 4 4 7 7
    2 2 5 5 8 8
\end{filecontents}

\begin{document}
    \pgfplotstableset{
        every even column/.style={
            column name={$X$}
        },
        every odd column/.style={
            column name={$Y$},
            column type/.add={}{|}
        }
    }
    \pgfplotstableread{mydata.dat}\loadedtable
    \pgfplotstabletypeset{\loadedtable}
\end{document}