Format long numbers with a thousand separator?

Question

In most language, long numbers are split into groups of three digits, to increase readability.

In Dutch (my native language), 1000000 is usually written as 1 000 000. In English, this would be 1,000,000.

Now, I would like to know how to use this kind of formatting in LaTeX. I searched google, but I only found some articles that explain how to split very long numbers over multiple lines, which is not what I need.

Is there a package that does this automatically? Or a certain tag I can use for this?

Answer 1

You can use \, for a thin space if you are entering by hand: $1\,000\,000$

You can also use a package such as siunitx, which inserts appropriate separators and spacing automatically: \num{100000}

Which one you should use depends on what you want to do (and where the numbers are generated); whether it's a few numbers in a hand-authored text or if you are typesetting thousands of numbers in table data where hand editing to add grouping separator is not really an option.

Answer 2

There is a good package for all of these formatting issues with numbers, either in text or in tabular: \usepackage{numprint}. Please study the manual, it provides a lot of detailed information. You get the manual usually with something like texdoc numprinton the command line.

A small MWE for numprint to answer your question:

\documentclass[english]{article}

\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{babel}
\usepackage{numprint}
\npthousandsep{\,}

\begin{document}

This would be a line with a price tag: \numprint{1000000} EUR.

And as a tabular: 
\begin{tabular}{N{7}{0}}
  1000000 {~EUR}\\
\end{tabular}
\end{document}

We get this:

As you can see, just tell numprint how the thousand separator should look like. You can do much more, rounding numbers e.g.

Answer 3

This is very interesting exercise for TeX macro programmers. My result looks like this:

\def\num #1{\numA#1\empty\empty\empty#1\end}
\def\numA #1#2#3{%
   \ifx #1\empty \afterelax{\numB}\fi
   \ifx #2\empty \afterelax{\numB{}}\fi
   \ifx #3\empty \afterelax{\ea\numB\ignoreit}\fi
   \ea \numA \ignoreit \relax
}
\def\numB #1#2#3#4{#1#2#3\ifx#4\end\else \numseparator \ea\numB\ea#4\fi}

\def\afterelax#1#2\relax{\fi#1}
\def\ignoreit#1{}
\let\ea=\expandafter

\def\numseparator{,}

Test: number \num{1234567}

The \num macro is expandable.

Answer 4

Well, the package SIUNITX has solved this problem easily. Try\usepackage[round-mode=places,round-precision=2,group-separator={,},output-decimal-marker={.}]{siunitx} in your preamble, and use \num{10000}. For more usages see its CTAN manual.

Answer 5

Use the package "Ziffer" which helps if you want to write 100000 as "100.000,00" it will show "10 000,00" (no space after the comma and a space instead of the dot)