pgfmath
Why does \pgfmathresult display the result of 3×4 as 12.0?
\documentclass{article}
\usepackage{pgf}
\begin{document}
\pgfmathparse{3*4}
\pgfmathresult
\end{document}
This code yields a document whose sole contents is "12.0".
In some parts of the document I'm working on, I'll need decimal places, but not for grade 2 math.
How do I fix this?
You can use the optional arguments of \pgfmathprintnumber to either cut off the decimal part or to round the number to an integer. Alternatively, you can use the \num macro from the siunitx package to round the number:
\documentclass{article}
\usepackage{tikz}
\usepackage{siunitx}
\begin{document}
\pgfmathsetmacro\testnumber{25.7}
\pgfmathprintnumber{\testnumber}
\pgfmathprintnumber[int trunc]{\testnumber}
\pgfmathprintnumber[fixed,precision=0]{\testnumber}
\num{\testnumber}
\num[round-mode=figures]{\testnumber}
\end{document}
You need to process the value \x using one of the PGF math functions and then set \pgfmathresult:
\documentclass{article}
\usepackage[margin=1in]{geometry}
\usepackage{tikz}
\usepackage{graphicx}
\begin{document}
\noindent
\begin{tikzpicture}
\node[anchor=south west,inner sep=0pt] (image) at (0,0) {\includegraphics[width=4.5in]{example-image-a}};
\begin{scope}[x={(image.center |- {(0,0)})},y={(image.center -| {(0,0)})}]
\draw[help lines,xstep=0.1,ystep=0.1,yellow!20] (0,0) grid (2,2);
\pgfkeys{/pgf/number format/precision=1}
\foreach \x in {0,0.1,...,2}
{
\node [anchor=north] at (\x,0) {\rotatebox{-90}{\pgfmathroundtozerofill{\x}\pgfmathresult}};
}
\end{scope}
\draw[line width=4pt,red] (image.south west) rectangle (image.north east);
\end{tikzpicture}
\end{document}
Above I've used \pgfmathroundtozerofill{\x}\pgfmathresult} which processed \x and pads it to 1 zero.
Best Answer
First, you are not formatting the number when you say
\pgfmathresult. Second, you have not specified any particular format for number printing. (Although the default format will do, in this case.)Compare:
PGF doesn't know you are typesetting Grade 2 maths rather than a doctoral dissertation in nuclear engineering!