Failure in first column alignment of completely left aligned threeparttable cells

Question

I have a long table with a height of 0.75 page height. I want all columns be left aligned. I tried this:

\documentclass{cta-author}

\usepackage{booktabs}
\usepackage{subcaption}
\usepackage{threeparttable}
\usepackage{pifont}
\usepackage{hyperref}


\begin{document}
\begin{table}[htp]

\begin{threeparttable}
\caption{My table}\label{tab:1}
\begin{tiny}
\begin{tabular}[width=\linewidth]{p{0.12\linewidth}p{0.3\linewidth}p{0.06\linewidth}p{0.07\linewidth}p{0.09\linewidth}p{0.09\linewidth}}
\toprule
Paper&method&p1&p2&p3&p4\\
\midrule 


\cite{c1} &method1 method1 method 1&\checkmark & \checkmark&\checkmark &\ding{55}\\
\rule{0pt}{4ex}

\cite{c2} &method2&\checkmark &\checkmark &\ding{55}&\ding{55}\\
\rule{0pt}{4ex}

\cite{c3}&method3 method3 method3 method3 &\ding{55} & \checkmark &\checkmark &\ding{55}\\
\rule{0pt}{4ex}
\midrule
my experiment test 123&method 4 method4&\checkmark &\ding{55} & \checkmark &\checkmark\\
\bottomrule
\end{tabular}
\begin{tablenotes}
\item *note
\end{tablenotes}


\end{tiny}
\end{threeparttable}
\end{table}


\end{document}

But using this all the columns are left aligned except the first column which contains paper citations. When I try using lp instead of p ( \begin{tabular}[width=\linewidth]{lp{0.12\linewidth}lp{0.3\linewidth}lp{0.06\linewidth}lp{0.07\linewidth}lp{0.09\linewidth}lp{0.09\linewidth}}) although all cells get left aligned correctly, but my table width gets more than one column and violates to the second column context. How can I have a one column width- left aligned threeparttable in a twoColumn page?

I am using IET paper template which is IET-Submission-DoubleColumn-Template.

This is my first column which has problem (all other columns are left aligned):

I used Foxit gridlines here, but in TexWorks pdf output is the same.

Answer 1

The reason why some, but not all, cells in the first column are indented slightly is that you didn't terminate the \rule{0pt}{4ex} instructions on the preceding lines with % characters. TeX converts the newline characters that follow the \rule{0pt}{4ex} instructions into whitespace, and that's what's showing up in your table.

I would also replace \begin{tabular}[width=\linewidth]{...} with \begin{tabular*}{\linewidth}{@{\extracolsep{\fill}} ...} and, relatedly, \end{tabular} with \end{tabular*}.

A separate issue: Since you don't use \tnote instructions, it's not clear to me why you use a tablenotes environment.

\documentclass{article}% %% I don't have the "cta-author" document class file(s)

\usepackage{booktabs}
\usepackage[skip=0.333\baselineskip]{caption}
\usepackage{threeparttable}
\usepackage{pifont}

\usepackage{array} % for "\newcolumntype" macro
\newcolumntype{P}[1]{>{\raggedright\arraybackslash}p{#1}}
\newcolumntype{C}[1]{>{\centering\arraybackslash}p{#1}}

\usepackage{hyperref}
\begin{document}

\begin{table}[htp]
\begin{threeparttable}
\caption{My table}\label{tab:1}
%\tiny %% why "\tiny"?
\begin{tabular*}{\linewidth}{@{\extracolsep{\fill}} 
  P{0.20\linewidth} P{0.30\linewidth} *{4}{C{0.06\linewidth}} }
\toprule
Paper&method&p1&p2&p3&p4\\
\midrule 
\cite{c1} &method1 method1 method1\tnote{*}&\ding{51} & \ding{51}&\ding{51}&\ding{55}\\
\rule{0pt}{4ex}% % <-- note the comment symbol at end of line
\cite{c2} &method2&\ding{51}&\ding{51}&\ding{55}&\ding{55}\\
\rule{0pt}{4ex}% % <-- note the comment symbol at end of line
\cite{c3}&method3 method3 method3 method3 &\ding{55} & \ding{51} &\ding{51} &\ding{55}\\
\midrule % <-- "\midrule" must come before "\rule{0pt}{4ex}"
\rule{0pt}{4ex}% % <-- note the comment symbol at end of line
my experiment test 123&method 4 method4&\ding{51} &\ding{55} & \ding{51} &\ding{51}\\
\bottomrule
\end{tabular*}

\smallskip
\begin{tablenotes}[flushleft]
\item[*] Note
\end{tablenotes}

\end{threeparttable}
\end{table}
\end{document}

Answer 2

• Sorry, I haven't document class which you use. I replace it with article.
• To me is not very clear, what is your problem beside erroneous use of table width and rule for distance between table rows
• if you like to have more vertical space, you can use \addlinespace from the booktabs. It can have options for more vertical space, for example \addlinespace[4ex] which inser vertical space of 4x between rows (why you like to have so much space?)

\documentclass{article}%{cta-author}
\usepackage{pifont}
\usepackage{amssymb}
\usepackage{array, booktabs, threeparttable}
\usepackage[skip=1ex]{caption}
\usepackage{hyperref}


\begin{document}
    \begin{table}[htp]
    \setlength\tabcolsep{0pt}
\begin{threeparttable}
\caption{My table}
\label{tab:1}
\begin{tabular*}{\linewidth}{@{\extracolsep{\fill}}
                             l >{\raggedright}p{0.5\linewidth} c c c c}
    \toprule
Paper       & method    
                & p1            & p2            & p3            & p4        \\
    \midrule
\cite{c1}   & method1 method1 method 1                        
                & \checkmark    & \checkmark    & \checkmark    & \ding{55} \\
    \addlinespace
\cite{c2}   & method2
                & \checkmark    & \checkmark    & \ding{55}     & \ding{55} \\
    \addlinespace
\cite{c3}   & method3 method3 method3 method3 method3 method3 method3 method3 
                & \ding{55}     & \checkmark    & \checkmark    & \ding{55} \\
    \midrule
my experiment test 123
            & method4 method4
                & \checkmark    & \ding{55}     & \checkmark    & \checkmark\\
\bottomrule
\end{tabular*}
\begin{tablenotes}[flushleft]\footnotesize
\item *note
\end{tablenotes}
\end{threeparttable}
    \end{table}
\end{document}