我不完全理解它chngcntr的工作原理。我附上了一个示例，希望能解释我的困惑，当然还有源代码。
1.1, 1.2,...我想要的是将第一部分编号为，将第二部分编号为2.1.1, 2.1.2, 2.2.1, 2.2.2,...，然后将第三部分编号回到3.1, 3.2, ...。
\documentclass[]{article}
\usepackage{chngcntr}
\newtheorem{thm}{Theorem}[section]
\begin{document}
\section{Labels 1.1, 1.2, ...}
\begin{thm} Theorem 1 \end{thm}
\subsection{New Subsection \textit{Does Not} Change Counter}
\begin{thm} Theorem 2 \end{thm}
\subsection{And Again}
\begin{thm} Theorem 3 \end{thm}
------------------------------
\section{Labels 1.1.1, 1.1.2, 1.2.1, ...}
\counterwithin{thm}{subsection}
\subsection{Subsection}
\begin{thm} Theorem 1 \end{thm}
\begin{thm} Theorem 2 \end{thm}
\subsection{New Subsection \textit{Does} Change Counter}
\begin{thm} Theorem 3 \end{thm}
\begin{thm} Theorem 4 \end{thm}
------------------------------
\section{Now I Try to Go Back to the First Case...}
\counterwithin{thm}{section}
\subsection{Subsection 1}
\begin{thm} Theorem 1 \end{thm}
\subsection{Subsection 2 -- Counter Is Reset to the Start}
\begin{thm} Theorem 2 \end{thm}
\end{document}
答案1
除了不推荐的编号方案之外……
\newtheorem{thm}{Theorem}[section]使thm计数器通过 进行重置section。
现在，也\counterwithin{thm}{subsection}将其设置thm在重置列表中subsection。只要\subsection使用，这就可以了。
切换回
\counterwithin{thm}{section}
稍后是不够的，因为thm仍在 的重置列表中subsection，因此任何未加星号的\subsection命令都会重置thm计数器。这是错误的，并且不是要求的，因此thm必须先将计数器从重置列表中删除：
\counterwithout{thm}{subsection}
\counterwithin{thm}{section}
恢复编号并重新设置。
\documentclass[]{article}
\usepackage{chngcntr}
\newtheorem{thm}{Theorem}[section]
\begin{document}
\section{Labels 1.1, 1.2, ...}
\begin{thm} Theorem 1 \end{thm}
\subsection{New Subsection \textit{Does Not} Change Counter}
\begin{thm} Theorem 2 \end{thm}
\subsection{And Again}
\begin{thm} Theorem 3 \end{thm}
------------------------------
\section{Labels 1.1.1, 1.1.2, 1.2.1, ...}
\counterwithin{thm}{subsection}
\subsection{Subsection}
\begin{thm} Theorem 1 \end{thm}
\begin{thm} Theorem 2 \end{thm}
\subsection{New Subsection \textit{Does} Change Counter}
\begin{thm} Theorem 3 \end{thm}
\begin{thm} Theorem 4 \end{thm}
------------------------------
\section{Now I Try to Go Back to the First Case...}
\counterwithout{thm}{subsection}
\counterwithin{thm}{section}
\subsection{Subsection 1}
\begin{thm} Theorem 1 \end{thm}
\subsection{Subsection 2 -- Counter Is Reset to the Start}
\begin{thm} Theorem 2 \end{thm}
\end{document}
