LaTeX表格编译报错：Illegal character in array arg. 求修复方案

Hey, let's break down why you're hitting that ! LaTeX Error: Illegal character in array arg. message and fix it up quickly.

错误根源 #

The main issue is super straightforward: in your tabular environment's column specifier ({1 1 1 1 1}), you used the Arabic numeral 1—but LaTeX only accepts valid column alignment identifiers here, like l (left-aligned), c (centered), or r (right-aligned). Numbers aren't allowed in this position, which triggers the illegal character error.

On top of that, there are two small syntax issues in your code that need fixing:

• You used HTML-escaped & instead of LaTeX's native column separator &
• Your \multicolumn commands are missing curly braces around the final content argument (LaTeX requires the format \multicolumn{num}{spec}{content})

修复后的完整代码 #

Here's the corrected version of your table code that should compile without errors:

%Table
\begin{table}
\caption{Drag Breakdown - Component method}
\label{table:PWDT}
\centering
\small
\renewcommand{\arraystretch}{1.25}
\begin{tabular}{l c c c c} 
\hline\hline
\multicolumn{1}{c}{\textbf{Components}} &
\multicolumn{1}{c}{\textbf{C$_{d-sf}$}} &
\multicolumn{1}{c}{\textbf{C$_{do}$}} &
\multicolumn{1}{c}{\textbf{C$_{di}$}} &
\multicolumn{1}{c}{\textbf{C$_{D}$}} \\
\multicolumn{1}{c}{(1)} &
\multicolumn{1}{c}{(2)} &
\multicolumn{1}{c}{(3)} &
\multicolumn{1}{c}{(4)} &
\multicolumn{1}{c}{(5)} \\
\hline
Wing & 0.1 & 0.2 & 0.3 & 0.4 \\
\hline
\multicolumn{2}{l}{} \\
\hline\hline
\end{tabular}
\normalsize
\end{table}

关键修复点总结 #

• Fixed column specifier: Changed {1 1 1 1 1} to {l c c c c} (you can adjust this to all c for full centering, or mix l/r as needed for specific columns)
• Replaced escaped characters: Swapped all & with LaTeX's standard & column separator
• Corrected \multicolumn syntax: Added curly braces around the content part of each \multicolumn command (e.g., \multicolumn{1}{c}{\textbf{Components}} instead of \multicolumn{1}{c}\textbf{Components})

内容的提问来源于stack exchange，提问作者Kushal