How can I left align a caption for a centered table?

Question

I want to left-align the caption of a table.

I read How can I left-align a caption? and the manual without luck.

This code:

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[font=small,labelfont=bf]{caption}
\begin{document}
\begin{table}
    \centering
    \captionsetup{singlelinecheck = false, justification=justified}
    \caption{System specifications}
    \label{tab:specs}
    \begin{tabular}{ll}
         Processor & Intel(R) Core(TM) i7-7500U CPU @2.70GHz 2.90 GHz \
         Installed RAM & 8.00 GB (7.89 GB usable)
    \end{tabular}
\end{table}
\end{document}

Creates this:

I want the caption to be justified with the left border of the table itself and not the paragraph:

(NB: picture above is edited in MS paint...)

With use of threeparttable. Please extend your code snišped to complete small document (MWE) that we can more easy show how. — Zarko, Feb 01 '21 at 12:15
The caption always fills the available width (with white space). Another solution is to reduce the width using a minipage (once you know how wide the tabular is). — John Kormylo, Feb 01 '21 at 12:29
Zarko, Like this? Sorry if I am mistaken - I am new to tex.stackexchange. — DisabledWhale, Feb 01 '21 at 12:55

score 3 · Accepted Answer · answered Feb 01 '21 at 13:31

3

Note the addition of @{} to each side of the tabular.

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[font=small,labelfont=bf]{caption}
\begin{document}
\begin{table}
  \sbox0{\begin{tabular}{@{}ll@{}}
         Processor & Intel(R) Core(TM) i7-7500U CPU @2.70GHz 2.90 GHz \
         Installed RAM & 8.00 GB (7.89 GB usable)
    \end{tabular}}%
  \centering
  \begin{minipage}{\wd0}
    \captionsetup{singlelinecheck = false, justification=justified}
    \caption{System specifications}
    \label{tab:specs}
    \usebox0
  \end{minipage}
\end{table}
\end{document}

answered Feb 01 '21 at 13:31

John Kormylo

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Aha! Thanks! So the intuition is that you create a box with the tabular inside. This box is then referred to inside the centered minipage (relative to the paragraph), which allows the justification to refer to the end of the box instead of the paragraph? – DisabledWhale Feb 01 '21 at 13:41
1

You can also use \settowidth or \widthof (calc package), but internally they are using saveboxes. This way you only have to format the box once. Note: one should only use box registers 0-9 inside groups (environments). – John Kormylo Feb 01 '21 at 22:31

score 3 · Answer 2 · answered Feb 01 '21 at 15:46

I suggest you (a) keep loading the caption package and (b) employ a threeparttable environment to encase both the \caption directive and the tabular environment. It measures the width of the tabular environment and limits the width of the caption string to that width.

\documentclass{article}
\usepackage{caption}
\usepackage{threeparttable} % see https://ctan.org/pkg/threeparttable
\begin{document}
\begin{table}[h!]
    \centering
    \captionsetup{singlelinecheck = false, justification=raggedright}
    \begin{threeparttable}
    \caption{System specifications}
    \begin{tabular}{@{} ll @{}}
         Processor & Intel(R) Core(TM) i7-7500U CPU @2.70\,GHz 2.90\,GHz \\
         Installed RAM & 8.00 GB (7.89 GB usable)
    \end{tabular}
    \end{threeparttable}
\end{table}
\end{document}

How can I left align a caption for a centered table?

2 Answers2