附加到参数

Question

我有一个接收一些参数的命令，例如：

\newcommand{\myappend}[1]{
\ifthenelse{\equal{#1}{aaaBB}}{\dothis}{\dothat}
}

假设参数为 'aaa'。如何将 'BB'（在命令内部）附加到 #1，即如何编辑 #1 ？

Answer 1

我不确定我是否理解了这个问题。这里有两个选项：第一个，使用辅助命令添加“BB”，#1第二个做同样的事情，但使用包\StrSubstitute中的命令xstring：

\documentclass{article}
\usepackage{ifthen}
\usepackage{xstring}

\def\dothis{this}
\def\dothat{that}

\newcommand\myappend[1]{%
  \def\x{#1BB}%
  \ifthenelse{\equal{\x}{aaaBB}}{\dothis}{\dothat}%
}

\newcommand\myappendi[1]{%
  \StrSubstitute{#1}{aaa}{aaaBB}[\x]%
  \ifthenelse{\equal{\x}{aaaBB}}{\dothis}{\dothat}%
}

\begin{document}

\myappend{aaa}\ \myappend{aaaBB}

\myappendi{aaa}\ \myappendi{aaaBB}

\end{document}

Answer 2

来自：\ifstrequal​etoolbox

\documentclass{article}
\usepackage{etoolbox}
\newcommand{\myappend}[1]{%
\ifstrequal{#1}{aaaBB}{}{aaaBB}
}%
\begin{document}
  \myappend{aaa}
\end{document}

和

\documentclass{article}
\usepackage{ifthen}
\newcommand{\myappend}[1]{%
\ifthenelse{\equal{#1}{aaaBB}}{}{aaaBB}
}%
\begin{document}
  \myappend{aaa}
\end{document}

Answer 3

通过原语可以轻松进行 pdfTeX 下的字符串比较\pdfstrcmp：

\documentclass{article}
% \pdfstrcmp{<string1>}{<string2>}
% \pdfstrcmp compares two strings and expands to 0 if the strings are equal, to -1 if the first string
%   ranks before the second, and to 1 otherwise
\newcommand{\myappend}[1]{%
  \ifnum\pdfstrcmp{#1}{aaa}=0
    This% Strings are equal
  \else
    That% Strings are not equal
  \fi%
}
\begin{document}
\myappend{aab} % That
\myappend{aaA} % That
\myappend{aaa} % This
\myappend{AAa} % That

\newcommand{\aaa}{aaa}
\myappend{\aaa} % This
\end{document}