pgfmath: rounded number without pgfmathprintnumber

Question

If I have a decimal number, say 0.09155, but I want to display a rounded version with two digits after the point: 0.09.
The standard way is to use pgfmathprintnumber[fixed, precision=2]{0.09155}.
So my question is: can I get the wanted value, here 0.09,  by pgfmath-calculation, that means without using pgfmathprintnumber?
documentclass[margin=5pt, varwidth]{standalone}
usepackage{tikz}
begin{document}
pgfmathsetmacrox{0.09155}

$x = x$, but 
$x approx pgfmathprintnumber[fixed, precision=2]{x}$
end{document}

Skillmon · Accepted Answer

The following defines a roundn function for pgfmath that takes two arguments, one being the number to be rounded, the second being the number of places you want the number to round to.
documentclass[]{article}

usepackage{pgfmath}
pgfmathsetmacrox{0.09155}
pgfmathdeclarefunction{roundn}{2}
  {pgfmathparse{round(#1 * 10^(#2)) / (10^(#2))}}

begin{document}
$x = x$, but
$x approx pgfmathparse{roundn(x,2)}pgfmathresult$
end{document}

Steven B. Segletes · Answer

Here's a home-grown version with tokcycle (i.e., no pgf). It rounds to a level specified in savedigits. documentclass{article} usepackage{tokcycle} newcounter{decs} defsavedigits{2} newififerr newififfounddot newcommandroundit[1]{% errfalse setcounter{decs}{0}% founddotfalse% MADE T WHEN DECIMAL HAS BEEN 1ST LOCATED tokcycle% CYCLE THROOUGH EACH TOKEN {tctestifx{.##1}% {addcytoks{##1}% iffounddoterrtruefifounddottruesetcounter{decs}{0}}% IF . {tctestifnum{`##1>`/}% {tctestifnum{`##1<`:}% {% iffounddotstepcounter{decs}fi% ifnumthedecs `9 }% {errtrue}% IF ASCII < `0 }% }% APPLY ABOVE LOGIC FOR CHAR TOKENS {errtrue}% IF BRACES {errtrue}% IF CONTROL SEQUENCE {}% IGNORE SPACES {#1}% THE ARGUMENT addcytoks{space} iferr ERRORelsethecytoksfi } newcommandroundlast[2]{ifnum0#2>4 thenumexpr#1+1 else#1fi} begin{document} noindent 0) roundit{0.09155} 1) roundit{12.3} 2) roundit{0.127} 3) roundit{1.2.3} 4) roundit{1.3today} 5) roundit{321.345 678} 6) roundit{000321.305} 7) roundit{.006 300 345} 8) roundit{0003x1.345} 9) roundit{1230} 9a) roundit{1230.} A) roundit{123.078} B) roundit{0003;345} end{document}

AndréC · Answer

Why not with xfp package?

documentclass[margin=5pt, varwidth]{standalone}
usepackage{tikz}
usepackage{xfp}
begin{document}
pgfmathsetmacrox{0.09155}

$x = x$, but 
$x approx pgfmathprintnumber[fixed, precision=2]{x}$

bigskip
With xfp package:

$x = x$, but 
$x approx fpeval{round(x,2)}$

end{document}

pgfmath: rounded number without pgfmathprintnumber

3 Answers

Add your own answers!

Ask a Question