以下是一个例子：
\documentclass{article}
\usepackage[papersize={4.8 in, 6.4 in}, top=0.10cm, bottom=0.5cm, right=0.2cm, left=0.2cm]{geometry}
\begin{document}
\begin{center}
\scriptsize
\begin{tabular}{|l|l|}
\multicolumn{2}{c}{\enspace} \\
left-aligned text in column 1 & left-aligned text in column 2 \\
left-aligned text in column 1 & left-aligned text in column 2 \\
\multicolumn{2}{c}{\enspace} \\
\multicolumn{2}{l}{\hspace{20pt} short line (left-aligned centered block)} \\
\multicolumn{2}{l}{\hspace{20pt} now a longer (line in the same left-aligned centered block)} \\
\multicolumn{2}{c}{\enspace} \\
\multicolumn{2}{c}{short line (centered, not left-aligned)} \\
\multicolumn{2}{c}{this is a longer line (centered, not left-aligned)} \\
\multicolumn{2}{c}{\enspace} \\
left-aligned text in column 1 & left-aligned text in column 2 \\
left-aligned text in column 1 & left-aligned text in column 2 \\
\end{tabular}
\end{center}
\end{document}
我有一张两列表格，我需要将跨越两列的文本居中并保持左对齐。
在上面的代码中，我使用左对齐多列和 \hspace 将块任意缩进 20pt。
有什么方法可以让编译器计算缩进的宽度/长度？
块居中的合适缩进应该是这样的：（表格宽度 - 平均行长）/ 2。
正确的做法是什么？
更新：
我选择了嵌套表格并获得了与原始表格几乎相同的布局：
答案1
使用 stackengine和它的\Centerstack命令，它可以采用可选的对齐参数（默认为c），以及\addlinespace（从booktabs）来简化这些块周围的垂直间距：
\documentclass{article}
\usepackage[papersize={4.8 in, 6.4 in}, top=0.10cm, bottom=0.5cm, hmargin=0.2cm]{geometry}
\usepackage{booktabs}
\usepackage[usestackEOL]{stackengine}
\begin{document}
\begin{center}
\scriptsize\setlength{\defaultaddspace}{2.7ex}
\begin{tabular}{|l|l|}
\multicolumn{2}{c}{\enspace} \\
left-aligned text in column 1 & left-aligned text in column 2 \\
left-aligned text in column 1 & left-aligned text in column 2 \\
\addlinespace
\multicolumn{2}{c}{\Centerstack[l]{short line (left-aligned centered block) \\
now a longer (line in the same left-aligned centered block)}} \\
\addlinespace
\multicolumn{2}{c}{\Centerstack{short line (centered, not left-aligned) \\
this is a longer line (centered, not left-aligned)}} \\
\addlinespace
left-aligned text in column 1 & left-aligned text in column 2 \\
left-aligned text in column 1 & left-aligned text in column 2 \\
\end{tabular}
\end{center}
\end{document}
编辑：加载eqparbox，您可以使用以下代码获取此对齐：
\begin{center}
\scriptsize\setlength{\defaultaddspace}{2.7ex}
\begin{tabular}{|l|l|}
\multicolumn{2}{c}{\enspace} \\
left-aligned text in column 1 & left-aligned text in column 2 \\
left-aligned text in column 1 & left-aligned text in column 2 \\
\addlinespace
\multicolumn{2}{c}{\eqparbox{LC}{\Centerstack[l]{short line (left-aligned centered block) \\
now a longer (line in the same left-aligned centered block)}}} \\
\addlinespace
\multicolumn{2}{c}{\eqparbox{LC}{\Centerstack[l]{short line (centered, not left-aligned) \\
this is a longer line (centered, not left-aligned)}}} \\
\addlinespace
left-aligned text in column 1 & left-aligned text in column 2 \\
left-aligned text in column 1 & left-aligned text in column 2 \\
\end{tabular}
\end{center}
答案2
通过以下两个小技巧，您可以获得两条彼此左对齐但在表格内居中的行。
在第一个例子中，我对两行文本都使用了单一居中p类型的列，而第二个例子则基于居中多列内的嵌套左对齐表格。
\documentclass{article}
\usepackage{array}
\usepackage{makecell}
\usepackage[papersize={4.8 in, 6.4 in}, top=0.10cm, bottom=0.5cm, right=0.2cm, left=0.2cm]{geometry}
\begin{document}
\begin{center}
\scriptsize
\begin{tabular}{|l|l|}
\multicolumn{2}{c}{\enspace} \\
left-aligned text in column 1 & left-aligned text in column 2 \\
left-aligned text in column 1 & left-aligned text in column 2 \\
\multicolumn{2}{c}{} \\
\multicolumn{2}{>{\centering\arraybackslash}p{8cm}}{short line (centered, not left-aligned)
\newline
this is a longer line (centered, not left-aligned)} \\
\multicolumn{2}{c}{} \\
left-aligned text in column 1 & left-aligned text in column 2 \\
left-aligned text in column 1 & left-aligned text in column 2 \\
\multicolumn{2}{c}{} \\
\multicolumn{2}{c}{\begin{tabular}{@{}l@{}}
short line (centered, not left-aligned) \\
this is a longer line (centered, not left-aligned)
\end{tabular}} \\
\multicolumn{2}{c}{} \\
left-aligned text in column 1 & left-aligned text in column 2 \\
left-aligned text in column 1 & left-aligned text in column 2 \\
\end{tabular}
\end{center}
\end{document}
答案3
通过使用\makecell，\mbox您的表格也可以按以下方式编写：
\documentclass{article}
\usepackage[papersize={4.8 in, 6.4 in},
top=0.10cm, bottom=0.5cm, right=0.2cm, left=0.2cm]{geometry}
\usepackage{array, makecell}
\usepackage{xparse}
\NewExpandableDocumentCommand\mcc{O{2}m}
{\multicolumn{#1}{c}{#2}}
\begin{document}
\begin{center}
\scriptsize
\begin{tabular}{|l|l|}
\mcc{} \\
left-aligned text in column 1 & left-aligned text in column 2 \\
left-aligned text in column 1 & left-aligned text in column 2 \\
\mcc{} \\
\mcc{\mbox{%
\makecell[l]{short line (centered, not left-aligned)\\
this is a longer line
(centered, not left-aligned)}}
} \\
\mcc{} \\
left-aligned text in column 1 & left-aligned text in column 2 \\
left-aligned text in column 1 & left-aligned text in column 2 \\
\mcc{} \\
\mcc{short line (centered, not left-aligned)} \\
\mcc{this is a longer line (centered, not left-aligned)} \\
\mcc{} \\
left-aligned text in column 1 & left-aligned text in column 2 \\
left-aligned text in column 1 & left-aligned text in column 2 \\
\end{tabular}
\end{center}
\end{document}
