使用多列时的列宽

Question

任何建议使用多列来改善列宽，并添加标题（请参阅所需的表格样式）

这是我的代码、输出和所需的表格样式

\documentclass{article}
\usepackage[margin=2cm,a4paper]{geometry} % set page parameters suitably
\usepackage[T1]{fontenc}
\usepackage[english]{babel}
\usepackage{natbib}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{siunitx} % Paquete para insertar unidades
\usepackage{setspace}
\usepackage{bbm}
\usepackage{enumitem}                    
\usepackage{pdflscape}
\usepackage{newpxtext,newpxmath}
\usepackage{longtable} 
\usepackage{microtype}  % new
\usepackage[titletoc,title]{appendix}
\usepackage{booktabs, makecell, multirow, tabularx,
           threeparttable, tabulary}

%-------------------------------------------------------------------------------------

\begin{document}
%----------------------------------------------------------------------------------------
\begin{table}
\caption{Variables and measurement\label{appendix}}
\renewcommand{\arraystretch}{1.0} 
\begin{tabularx}{\textwidth}{@{}lXXS@{}}
\toprule
\multicolumn{1}{l}{Symbol}&\multicolumn{1}{l}{Variable Description}&\multicolumn{1}{l}{Measure}\\
\midrule
%-------
Leak Volume& Actions outside the utility such as excavation strikes, land movement, and weather &Utility-year \\
Incidents&line strikes or breaks but also from other system failures such as overpressurization. &Utility-year \\
Hazardous Leaks &significant incident occurrences as measures of safety performance &Utility-year \\

%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------
SO2_{it}&Total energy related $SO_{2}$ emission &$10^4$ ton \\
NOX_{it}&Total energy related $NO_{X}$ emission &$10^4 $ton \\

%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------
P_{it} &GDP per capita = GDP/total population & $10^4$ \$ \\

%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------

R_{it}&Population at the end of the year& $10^4$ persons\\

%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------

IS_{it}&Urbanization rate = $100\% \times$ Urban population/total population&\% \\

%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------

T_{it}&Industrial structure = $100\% \times$ The secondary GDP/total GDP&\%  \\

%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------

ES_{it} & Technology level $T_{it}$ = Economic output/energy consumption &$10^4$ \$ /ton \\

%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------
URevpc_{it}&Energy structure = Fossil energy/total energy & $10^4$ Chinese Yuan/ton \\

%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------
UEngel_{it}& Urban affordable revenue per capita = urban affordable revenue/total population & \% \\
%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------

SAVPR_{it}& State avg. gas price $(\$ /1k ft^3)$ & Utility-year \\

%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------
Ownership& public, private & Utility-year \\

%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------
TSD_{it}& Total state deliveries $(\$ /1k ft^3)$ &State \\

%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------
TSR_{it}& Total state receipts $(\$ /1k ft^3)$ &  State\\
%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------

%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------
MI_{it}& Median income $(\$)$ & Utility-year\\
%-
%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------
PRE_{it}&Annual precipitation of a major city in each state  & (mm)\\
%-
%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------
RHU_{it}&Annual average relative humidity of a major city in each state  & \% \\
%-
\bottomrule
\end{tabularx}
\end{table}
\end{document}

期望风格：

Answer 1

您定义了 4 列，但您的表只有 3 列。

\documentclass{article}
\usepackage[margin=2cm,a4paper]{geometry} % set page parameters suitably
\usepackage[T1]{fontenc}
\usepackage[english]{babel}
\usepackage{natbib}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{siunitx} % Paquete para insertar unidades
\usepackage{setspace}
\usepackage{bbm}
\usepackage{enumitem}                    
\usepackage{pdflscape}
\usepackage{newpxtext,newpxmath}
\usepackage{longtable} 
\usepackage{microtype}  % new
\usepackage[titletoc,title]{appendix}
\usepackage{booktabs, makecell, multirow, tabularx,
           threeparttable, tabulary}
\usepackage{caption}
%-------------------------------------------------------------------------------------

\begin{document}
%----------------------------------------------------------------------------------------
\begin{table}
\caption{Variables and measurement\label{appendix}}
\renewcommand{\arraystretch}{1.0} 
\begin{tabularx}{\textwidth}{@{}lXl@{}}
\toprule
\multicolumn{1}{@{}l}{Symbol}&\multicolumn{1}{l}{Variable Description}&\multicolumn{1}{l}{Measure}\\
\midrule
%-------
Leak Volume& Actions outside the utility such as excavation strikes, land movement, and weather &Utility-year \\
Incidents&line strikes or breaks but also from other system failures such as overpressurization. &Utility-year \\
Hazardous Leaks &significant incident occurrences as measures of safety performance &Utility-year \\

%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------
$\textrm{SO2}_{it}$&Total energy related $SO_{2}$ emission &$10^4$ ton \\
$\textrm{NOX}_{it}$&Total energy related $NO_{X}$ emission &$10^4 $ton \\

%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------
$\textrm{P}_{it} $&GDP per capita = GDP/total population & $10^4$ \$ \\

%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------

$\textrm{R}_{it}$&Population at the end of the year& $10^4$ persons\\

%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------

$\textrm{IS}_{it}$&Urbanization rate = $100\% \times$ Urban population/total population&\% \\

%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------

$\textrm{T}_{it}$&Industrial structure = $100\% \times$ The secondary GDP/total GDP&\%  \\

%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------

$\textrm{ES}_{it} $& Technology level $T_{it}$ = Economic output/energy consumption &$10^4$ \$ /ton \\

%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------
$\textrm{URevpc}_{it}$&Energy structure = Fossil energy/total energy & $10^4$ Chinese Yuan/ton \\

%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------
$\textrm{UEngel}_{it}$& Urban affordable revenue per capita = urban affordable revenue/total population & \% \\
%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------

$\textrm{SAVPR}_{it}$& State avg. gas price $(\$ /1k ft^3)$ & Utility-year \\

%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------
Ownership& public, private & Utility-year \\

%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------
$\textrm{TSD}_{it}$& Total state deliveries $(\$ /1k ft^3)$ &State \\

%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------
$\textrm{TSR}_{it}$& Total state receipts $(\$ /1k ft^3)$ &  State\\
%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------

%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------
$\textrm{MI}_{it}$& Median income $(\$)$ & Utility-year\\
%-
%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------
$\textrm{PRE}_{it}$&Annual precipitation of a major city in each state  & (mm)\\
%-
%----------------------------------------------------------------------------------------%---------------------------------------------------------------------------
$\textrm{RHU}_{it}$&Annual average relative humidity of a major city in each state  & \% \\
%-
\bottomrule
\end{tabularx}
\end{table}
\end{document}