Create LaTeX tables from plain numerical data?

Question

I have a bunch of MATLAB results like this

                   0  -2.000000000000000   2.000000000000000
   1.000000000000000  -1.926829268292683   3.707317073170731
   2.000000000000000   0.716910656478955  -6.475399900458298
   3.000000000000000   0.718921416773616   0.516843960338833

Here leftmost column is always 0,1,2,3,... so I have to get rid of those trailing zeros or to do row-numbering in LaTeX somehow.

However I want to convert all of them results to something like

But anything simple and informative would do. I generated the table above using MathType editor, so I'm not even sure what some of those commands mean

\begin{array}{*{20}{c}}
i&\vline& {{x_i}}&{{y_i}}\\
\hline
0&\vline& {{\rm{ - 2}}{\rm{.000000000000000}}}&{{\rm{2}}{\rm{.000000000000000}}}\\
1&\vline& {{\rm{ - 1}}{\rm{.926829268292683}}}&{{\rm{3}}{\rm{.707317073170731}}}\\
2&\vline& {{\rm{0}}{\rm{.716910656478955}}}&{{\rm{ - 6}}{\rm{.475399900458298}}}\\
3&\vline& {{\rm{0}}{\rm{.718921416773616}}}&{{\rm{0}}{\rm{.516843960338833}}}
\end{array}

What would you suggest?

Answer 1

If you are more or less in a hurry and do not want to delve too much into the works of datatools and/or pgfplotstable and your data is final, I would use the raw data and construct the tabular (with siunitx’ S column) manually.

With a decent editor you can column-select the space between your numbers and simply add & and \\ where needed.

The siunitx setup is pretty easy:

• table-format: specifies numbers of integer digits, decimal digits, …

• table-auto-round: rounds the input number according to table-format

• zero-decimal-to-integer: formats any trailing .0000… to a integer number

  (This is actually not needed as we already set the format for the first column to zero decimals and use the table-auto-round mode.)

In the example I set the x_i column to round at the fifth decimal, the y_i prints the decimals as they are, the rounding option has to be set off/false, because the number is too big for TeX.

I also used the booktabs package for nice tables but if you having other tabulars already in your document stay consistent!

Note that I have used a tabular not an array (math-mode). You need to add the table float environment and a table caption yourself (as usual).

The columns’ headers have to be hidden from the siunitx parser with a set of { } braces.

Code

\documentclass{article}
\usepackage{siunitx,booktabs}
\sisetup{
    table-auto-round
}
\begin{document}
\begin{tabular}{S[table-format=1.0]S[table-format=-1.5]S[table-format=-1.15,table-auto-round=false]}
    \toprule
    {$i$}             & {$x_i$}            & {$y_i$}            \\ \midrule
    0                 & -2.000000000000000 & 2.000000000000000  \\
    1.000000000000000 & -1.926829268292683 & 3.707317073170731  \\
    2.000000000000000 & 0.716910656478955  & -6.475399900458298 \\
    3.000000000000000 & 0.718921416773616  & 0.516843960338833  \\ \bottomrule
\end{tabular}
\end{document}

Output

Answer 2

pgfplotstable's syntax takes a bit of getting used to, but then it can really speed up your work, especially because it can read data files straight from the file system. Here's an example using your data:

\documentclass{article}
\usepackage{pgfplotstable, booktabs}
\begin{document}
\pgfplotstableread{ % Read the data into a macro we call \datatable
                   0  -2.000000000000000   2.000000000000000
   1.000000000000000  -1.926829268292683   3.707317073170731
   2.000000000000000   0.716910656478955  -6.475399900458298
   3.000000000000000   0.718921416773616   0.516843960338833
}\datatable
% If your data is in a file called data.csv, you could also just do:
%\pgfplotstableread{data.csv}\datatable

\pgfplotstabletypeset[
    columns/0/.style={column name={$i$}}, % Set the name to be used for the first column
    columns/1/.style={
        column name=$x_i$,  % ... and the second
        dec sep align,      % align on the decimal marker
        /pgf/number format/fixed zerofill,  % print trailing zeros
        /pgf/number format/precision=14     % print 14 digits
    },
    columns/2/.style={
        column name=$y_i$,
        dec sep align,
        /pgf/number format/fixed zerofill,
        /pgf/number format/precision=14
    },
    every head row/.style={
        before row=\toprule,    % booktabs rules
        after row=\midrule
    },
    every last row/.style={
        after row=\bottomrule
    }]{\datatable}
\end{document}

Answer 3

You can use the pgfplotstable package. It will let you read in datafiles and is able to output the data in many ways. Have a look through the manual. There are many examples for you to try.

Another option is the datatool package.