Unwanted spacing (grouping) of decimal-part when aligning numbers in table using Siunitx

Question

I get weird thinspaces inserted into my decimal-aligned columns when using the S column type of siunitx. It is easier to show the problem than explain in words.

The unwanted space is shown in the second column with the pink arrow marks.

Here is the MWE that produces this table

\documentclass{article}
\usepackage{siunitx}
\usepackage{booktabs}
\begin{document}
\begin{table}[!htb]
    \centering
    \begin{tabular}{@{}lS[table-format=1.6] S[table-format=3.2]@{}}
        \toprule
        {First} & {Second} & {Third} \\
        \midrule
        foo1    & 1.25     & 111     \\
        foo2    & 2.203762 & 222.2   \\
        foo3    & 3.3453   & 3.33    \\
        foo4    & 4.87902  & 4       \\
        \bottomrule
    \end{tabular}
\end{table}
\end{document}

How do I suppress these unwanted spaces?

Answer 1

Grouping digits can be turned off by using group-digits=false as shown in the following MWE. Its default value is true, as described in section '5.6 Printing numbers' (page 27) of the siunitx manual (to version 2.7s).

According to the manual, one can also separately activate the grouping for the integer and the decimal part of numbers by using one of the following choices: group-digits = decimal (to enable grouping only in the decimal part) or group-digits = integer (for grouping in the integer part only).

\documentclass{article}
\usepackage[group-digits=false]{siunitx}
\usepackage{booktabs}
\begin{document}
\begin{table}[!htb]
    \centering
    \begin{tabular}{@{}lS[table-format=1.6] S[table-format=3.2]@{}}
        \toprule
        {First} & {Second} & {Third} \\
        \midrule
        foo1    & 1.25     & 111     \\
        foo2    & 2.203762 & 222.2   \\
        foo3    & 3.3453   & 3.33    \\
        foo4    & 4.87902  & 4       \\
        \bottomrule
    \end{tabular}
\end{table}
\end{document}