我怎样才能在列表前面创建带有文本“where”的“where”环境？

Question

我想要做在哪里像图片中那样的环境？我该怎么做？还应该有在哪里环境中的文本。我已经用过在哪里下面的环境代码遍布我的文章，所以我想将它改为如图所示。

\newenvironment{where}[1]%
{\begin{list}{}{%
    \setlength\itemsep{0em}
    \renewcommand{\makelabel}[1]{%
        {##1}\hfil}%
    \settowidth{\labelwidth}{#1}%
    \setlength{\leftmargin}{%
        \labelwidth+\labelsep}}}%
{\end{list}}

Answer 1

快速而粗略，不使用列表，而是使用tabularx，并借助包的一些帮助calc。符号列在数学模式下设置。

\documentclass{article}
\usepackage{array} % for >{} and <{}
\usepackage{tabularx} % for tabularx
\usepackage{calc} % for \widthof
\newenvironment{where}{%
where \tabularx{\linewidth-\widthof{where }}[t]{>{$}r<{$} X}%
}{\endtabularx}

\begin{document}
Some text, then
\begin{equation}
a = bcd
\end{equation}
\begin{where}
a & is the \ldots \\
b & is \ldots \\
c & lorem ipsum dolor sit amet consectetur etc.\@ etc.\@ ad infinitum until this text has at least two lines \\
abcd & etc.
\end{where}
\end{document}

Answer 2

一种不同但可能更简单的方法也可以是itemize不使用项目符号，而是使用“where”，如下所示：

\documentclass{article}
\begin{document}

{\renewcommand\labelitemi{}
\begin{itemize}
    \item[where] $\gamma_F$ is the partial safety factor for \underline{load}
    \item $\gamma_M$ is the partial safety factor for \underline{resistance}
    \item $E_d$ is the design value of the force or moment caused by the load
\end{itemize}
}

\end{document}

您可以随时根据自己的喜好调整 itemize，例如\hspace{}在“where”后添加一个并选择所需的距离：或者在开始 itemize 环境后立即\item[where\hspace{0.4cm}] $gamma_F$ is...添加以减少垂直间距。示例：\itemsep0em

\documentclass{article}
\begin{document}

{\renewcommand\labelitemi{}
\begin{itemize}
    \itemsep0em
    \item[where \hspace{0.4cm}] $\gamma_F$ is the partial safety factor for \underline{load}
    \item $\gamma_M$ is the partial safety factor for \underline{resistance}
    \item $E_d$ is the design value of the force or moment caused by the load
\end{itemize}
}

\end{document}