很多时候，我需要用公共打印机打印试卷以检查其格式和布局。但是，如果有一个开关可以将所有文本替换为虚拟文本，那么考试的保密性就不会受到侵犯，那就太好了。
为了完整性，如果长文本可以用长虚拟文本替换，短问题文本也可以用长虚拟文本替换，那就完美了。换句话说，替换需要以单词为单位进行。
\documentclass{exam}
\begin{document}
\begin{questions}
\question[7]
some very long question body to be replaced by a very long dummy text.
some very long question body to be replaced by a very long dummy text.
some very long question body to be replaced by a very long dummy text.
some very long question body to be replaced by a very long dummy text.
some very long question body to be replaced by a very long dummy text.
some very long question body to be replaced by a very long dummy text.
some very long question body to be replaced by a very long dummy text.
some very long question body to be replaced by a very long dummy text.
\begin{parts}
\part[5] some text to be replaced by a dummy text
\begin{subparts}
\subpart[3] to be replaced by a dummy text
\begin{subsubparts}
\subsubpart[1] some question to be replaced by a dummy text
\end{subsubparts}
\end{subparts}
\begin{choices}
\choice a short text to be replaced by a short one.
\end{choices}
\end{parts}
\end{questions}
\end{document}
答案1
可以从这里调整一个强力（并且相当慢）的解决方案：如何进行多个字符串替换？
基本上，我定义了一个obfuscate环境，因此每个字母字符都被小写的 X 替换
\documentclass{exam}
\usepackage{xstring}
\usepackage{environ}
\def\obfuscatetext{0}
\newcommand{\xeverywhere}[2]{%
\expandafter\StrSubstitute\expandafter{\BODY}{#1}{#2}[\BODY]%
}
\NewEnviron{obfuscate}{{%
\ifnum\obfuscatetext=1
\expandarg
\StrSubstitute{\BODY}{a}{x}[\BODY]%
\xeverywhere{b}{x}%
\xeverywhere{c}{x}%
\xeverywhere{d}{x}%
\xeverywhere{e}{x}%
\xeverywhere{f}{x}%
\xeverywhere{g}{x}%
\xeverywhere{h}{x}%
\xeverywhere{i}{x}%
\xeverywhere{j}{x}%
\xeverywhere{k}{x}%
\xeverywhere{l}{x}%
\xeverywhere{m}{x}%
\xeverywhere{n}{x}%
\xeverywhere{o}{x}%
\xeverywhere{p}{x}%
\xeverywhere{q}{x}%
\xeverywhere{r}{x}%
\xeverywhere{s}{x}%
\xeverywhere{t}{x}%
\xeverywhere{u}{x}%
\xeverywhere{v}{x}%
\xeverywhere{w}{x}%
\xeverywhere{y}{x}%
\xeverywhere{z}{x}%
\xeverywhere{A}{x}%
\xeverywhere{B}{x}%
\xeverywhere{C}{x}%
\xeverywhere{D}{x}%
\xeverywhere{E}{x}%
\xeverywhere{F}{x}%
\xeverywhere{G}{x}%
\xeverywhere{H}{x}%
\xeverywhere{I}{x}%
\xeverywhere{J}{x}%
\xeverywhere{K}{x}%
\xeverywhere{L}{x}%
\xeverywhere{M}{x}%
\xeverywhere{N}{x}%
\xeverywhere{O}{x}%
\xeverywhere{P}{x}%
\xeverywhere{Q}{x}%
\xeverywhere{R}{x}%
\xeverywhere{S}{x}%
\xeverywhere{T}{x}%
\xeverywhere{U}{x}%
\xeverywhere{V}{x}%
\xeverywhere{W}{x}%
\xeverywhere{Y}{x}%
\xeverywhere{X}{x}%
\xeverywhere{Z}{x}%
\BODY
\else
\BODY
\fi
}}
\let\oldtextbf\textbf
\let\oldtextit\textit
\let\oldtexttt\texttt
\renewcommand{\textbf}[1]{\oldtextbf{\begin{obfuscate}#1\end{obfuscate}}}
\renewcommand{\textit}[1]{\oldtextit{\begin{obfuscate}#1\end{obfuscate}}}
\renewcommand{\texttt}[1]{\oldtexttt{\begin{obfuscate}#1\end{obfuscate}}}
\newcommand{\ObfuscateON}{%
\renewcommand{\obfuscatetext}{1}
}
\newcommand{\ObfuscateOFF}{%
\renewcommand{\obfuscatetext}{0}
}
\ObfuscateON
\begin{document}
%If I want normal text, I just delete the next line:
\ObfuscateON
\begin{obfuscate}
\begin{questions}
\question[7]
some very long question body to be replaced by a very long dummy text.
some very long question body to be replaced by a very long dummy text.
some very long question body to be replaced by a very long dummy text.
some very long question body to be replaced by a very long dummy text.
some very long question body to be replaced by a very long dummy text.
some very long question body to be replaced by a very long dummy text.
some very long question body to be replaced by a very long dummy text.
some very long question body to be replaced by a very long dummy text.
\begin{parts}
\part[5] some text to be replaced by a dummy text
\begin{subparts}
\subpart[3] to be replaced by a dummy text
\begin{subsubparts}
\subsubpart[1] some question to be replaced by a dummy text
\end{subsubparts}
\end{subparts}
\begin{choices}
\choice a short text to be replaced by a short one.
\end{choices}
\end{parts}
\end{questions}
\end{obfuscate}
\end{document}
可以添加数字和标点符号随意在定义中obfuscate
编辑：我添加了 \ObfuscateON 命令。默认情况下不执行任何操作，因此只有在使用 \ObfuscateON 时才会起作用。我还修补了、obfuscate的定义，因此可以正常工作。\textbf\textit\textttobfuscate
再次编辑：由于我的第一个解决方案有很多错误，所以我想出了一个不错的解决方案，使用lualatex和chickenize可以避免与其他包发生冲突。至于图形，使用draft选项就足够了。
%!TEX program = lualatex
\documentclass{exam}
\usepackage{luacode}
\usepackage[draft]{graphicx}
\usepackage{chickenize}
\begin{luacode*}
chickenizefraction = 100000
chickenstring[1] = "ayyyy"
chickenstring[2] = "lol"
chickenstring[3] = "lmao"
chickenstring[4] = "haha"
\end{luacode*}
\begin{document}
%Delete chickenize or use \unchickenize to get normal text
\chickenize
\begin{questions}
\question[7]
some very long question body to be replaced by a very long dummy text.
some very long question body to be replaced by a very long dummy text.
some very long question body to be replaced by a very long dummy text.
some very long question body to be replaced by a very long dummy text.
some very long question body to be replaced by a very long dummy text.
some very long question body to be replaced by a very long dummy text.
some very long question body to be replaced by a very long dummy text.
some very long question body to be replaced by a very long dummy text.
\begin{parts}
\part[5] some text to be replaced by a dummy text
\begin{subparts}
\subpart[3] to be replaced by a dummy text
\begin{subsubparts}
\subsubpart[1] some question to be replaced by a dummy text
\end{subsubparts}
\end{subparts}
\begin{choices}
\choice a short text to be replaced by a short one.
\end{choices}
\end{parts}
\end{questions}
\end{document}
