隐藏编号方程式中的数字的环境

Question

我想创建一个环境，隐藏编号方程中的方程编号。我应该像这样工作：

\documentclass{article}
\begin{document}
% ---------------------------
% \begin{nonumber}
\begin{equation}
a + b = c \quad \text{this equation should be unnumbered}
\end{equation}
% \end{nonumber}

\begin{equation}
a + b = c \quad \text{this equation should be numbered}
\end{equation}
\end{document}

Answer 1

如果您仅使用equations，则以下内容就足够了：

\documentclass{article}

\newenvironment{noeqnumber}
  {\renewenvironment{equation}{\[}{\]}}
  {}

\begin{document}

\begin{noeqnumber}
  \begin{equation}
    a + b = c \quad \mbox{this equation should be unnumbered}
  \end{equation}
\end{noeqnumber}

\begin{equation}
  a + b = c \quad \mbox{this equation should be numbered}
\end{equation}

\end{document}

请注意\nonumber已经存在，因此您必须使用不同的环境名称，例如noeqnumber。

---

如果您使用aligns，那么我们可以调整计数器步进和标签打印机制：

\documentclass{article}

\usepackage{mathtools}
\makeatletter
% New tag form that gobbles the number
\newtagform{gobble}[\@gobble]{}{}
\makeatother

\let\oldrefstepcounter\refstepcounter

\newenvironment{noeqnumber}
  {\renewcommand{\refstepcounter}[1]{%
     % Only step counter if it is not equation
     \ifnum\pdfstrcmp{##1}{equation}=0\else
       \oldrefstepcounter{##1}%
     \fi
   }%
   \usetagform{gobble}}
  {}

\begin{document}

\begin{noeqnumber}
  \begin{align}
    a + b &= c     \quad \text{this equation should be unnumbered} \\
        d &= e + f \quad \text{this equation should be unnumbered}
  \end{align}
\end{noeqnumber}

\begin{equation}
  a + b = c \quad \text{this equation should be numbered}
\end{equation}

\end{document}