How do I make Chinese character string to have the same length by filling blanks?

Question

I am trying to write a document for several people to sign, their names have different numbers of characters. I would like to make them to have the same length by filling blank spaces to them. For example, in the following document

% !TEX encoding = UTF-8 Unicode
% !TEX TS-program = xelatex
\documentclass[UTF8]{article}
\usepackage{ctex}
\begin{document}
\pagestyle{plain}
\maketitle
李梅：


王晓华：


张丽娟：
\end{document}

I would like it to produce

李 梅：
王晓华：
张丽娟：

where the colons should actually be aligned exactly, which is hard to produce.

The most intuitive way to me is writing a random character in the middle the first name and make that extra character white. But it seems cumbersome and not easily generalizable. Is there a better way?

Thank you in advance!

Answer 1

An easy way is to use a tabular:

\documentclass{article}

\begin{document}

\noindent
\begin{tabular}{@{}l@{:}}
  First\\
  Second\\
  Third
\end{tabular}

\end{document}

@{} suppresses or replaces space between columns, or before the first and after the last column—as used here.

Using your template with Chinese characters, this gives:

\documentclass[UTF8]{article}
\usepackage{ctex}

\begin{document}

\noindent
\begin{tabular}{@{}l@{:}}
  李梅\\
  王晓华\\
  张丽娟
\end{tabular}

\end{document}

In case you want to add spacing before the colons, you can start the tabular for instance with

\begin{tabular}{@{}l@{\kern 2pt:}}

If you want a second column that takes all remaining space until the right margin, you can use the X column type of tabularx (we tell tabularx to make the X column large enough so that the table fills the whole \linewidth; you can have several X columns if you wish, they will share the remaining space left by the other columns):

\documentclass{article}
\usepackage{tabularx}
\usepackage{lipsum}

\begin{document}

\noindent
\begin{tabularx}{\linewidth}{@{}l@{:}X@{}}
  First  & \lipsum[1][1-2]\\
  Second & \lipsum[2][1-2]\\
  Third  & \lipsum[3][1-2]
\end{tabularx}

\end{document}

You can start the tabularx this way to insert some spacing after the colon:

\begin{tabularx}{\linewidth}{@{}l@{:\enspace}X@{}}

Justifying the first column

Following up on a request in the comments, here is a little hack to get the first column automatically justified without needing to manually insert spaces between the characters. This definitely requires an Unicode-based engine, such as XeTeX or LuaTeX.

\documentclass[UTF8]{article}
\usepackage{ctex}
\usepackage{collcell}

\makeatletter
\newcommand*{\@insertHfills}[1]{%
  \unless\ifx#1\@nil
    #1\hfill \expandafter\@insertHfills
  \fi
}

% Append an \hfill after each token of #1 and set \parfillskip to zero
% after the result has been left in the TeX input stream.
\newcommand*{\insertHfills}[1]{%
  \@insertHfills#1\@nil
  \parfillskip=\z@\relax
}
\makeatother

% Define a special column type derived from l (r or c would do as well)
% that wraps the cell contents as the argument of \insertHfills.
\newcolumntype{E}{>{\collectcell\insertHfills}l<{\endcollectcell}}

\begin{document}

\noindent
\begin{tabular}{@{}E@{:}}
  李梅   \\
  王晓华 \\
  王j华  \\
  张丽娟
\end{tabular}

\end{document}