foreach loop print PGF parsed math

Question

Desired output: a table with row number and a function of that (say, row number plus one).

1	2
2	3
...	...
10	11

Attempt:

Here's my MWE adapted from Foreach inside a TikZ matrix.

\documentclass[tikz,preview]{standalone}
\usetikzlibrary{matrix}
\usepackage{etoolbox}
\begin{document}
\pgfkeys{/pgf/number format/.cd,fixed,int detect,precision=2}
\begin{tikzpicture}
    \let\mymatrixcontent\empty
    \foreach \myc in {1,...,10}{%
        \pgfmathparse{\myc+1}
        \xappto\mymatrixcontent{\expandonce{\myc &}}
        \xappto\mymatrixcontent{\expandonce{\pgfmathresult\}}
    }
    \matrix [matrix of nodes,ampersand replacement=&] {
        \mymatrixcontent
    };
\end{tikzpicture}
\end{document}

Question: how to drop the decimal part of the right column?

I tried using \pgfkeys{/pgf/number format/.cd,int detect,precision=2} from TikZ's Manual on Number Printing, but that changed nothing. Enclosing \pgfmathresult with \pgfmathprintnumber{} gives unexpected results.

Answer 1

I'm not sure what your aim is. Here's a fairly general method for outputting values depending on the row index.

\documentclass{article}
\usepackage{siunitx}
\ExplSyntaxOn
\NewDocumentCommand{\formulatable}{mmm}
 {% #1 = number of rows
  % #2 = format of the column
  % #3 = formula to typeset
  \gnusupporter_formulatable:nnn { #1 } { #2 } { #3 }
 }
\cs_new:Nn __gnusupporter_formulatable_do:n {}
\cs_new:Nn __gnusupporter_formulatable_cycle:n
 {
  #1 & __gnusupporter_formulatable_do:n { #1 } \
 }
\cs_new_protected:Nn \gnusupporter_formulatable:nnn
 {
  \cs_set:Nn __gnusupporter_formulatable_do:n { \fp_eval:n { #3 } }
  \begin{tabular}{rS[table-format=#2]}
  \int_step_function:nN { #1 } __gnusupporter_formulatable_cycle:n
  \end{tabular}
 }
\ExplSyntaxOff
\begin{document}
\formulatable{10}{2.0}{#1+1}
\qquad
\formulatable{10}{1.6}{round(exp(#1/10),6)}
\qquad
\formulatable{10}{1.4}{round(sind(#1),4)}
\end{document}

The second argument should be adjusted once you know the amount of digits in the second column.

We can add also a starting point, so we can typeset the table of sines for angles in degrees from 1 to 45, which would have been very helpful to Ptolemy.

\documentclass{article}
\usepackage{siunitx}
\ExplSyntaxOn
\NewDocumentCommand{\formulatable}{mO{1}mm}
 {% #1 = number of rows
  % #2 = starting point
  % #3 = format of the column
  % #4 = formula to typeset
  \gnusupporter_formulatable:nnnn { #1 } { #2 } { #3 } { #4 }
 }
\cs_new:Nn __gnusupporter_formulatable_do:n {}
\cs_new:Nn __gnusupporter_formulatable_cycle:n
 {
  #1 & __gnusupporter_formulatable_do:n { #1 } \
 }
\cs_new_protected:Nn \gnusupporter_formulatable:nnnn
 {
  \cs_set:Nn __gnusupporter_formulatable_do:n { \fp_eval:n { #4 } }
  \begin{tabular}{rS[table-format=#3]}
  \int_step_function:nnN { #2 } { #1+#2-1 } __gnusupporter_formulatable_cycle:n
  \end{tabular}
 }
\ExplSyntaxOff
\begin{document}
\formulatable{15}{1.4}{round(sind(#1),4)}
\quad
\formulatable{15}[16]{1.4}{round(sind(#1),4)}
\quad
\formulatable{15}[31]{1.4}{round(sind(#1),4)}
\end{document}