list of figures and tables when there are no figures or tables?

Question

I have a rather large project, from which I select portions based on needs. This selection is done using a complex system of \include and \input commands. I would like to generate a list of figures and a list of tables for the output, but in the case there are no figures the list of figures should not appear. The same should happen with tables.

Here is a MWE:

\documentclass[10pt,twocolumn]{article}
\usepackage{lipsum}
\usepackage[margin=0.75in]{geometry}
\usepackage{float}
\floatstyle{boxed}


\restylefloat{figure}
\restylefloat{table}

\def\ignoreTable#1\end{table}{}
\def\ignoreFigure#1\end{figure}{}
\begin{document}

\tableofcontents
\addcontentsline{toc}{section}{List of Figures}
\listoffigures
\addcontentsline{toc}{section}{List of Table}
\listoftables

\section{First section}
\lipsum[\inputlineno]
\ignoreFigure
\begin{figure}[H]\centering
\LaTeX\LaTeX
\caption{my figure}
\end{figure}
\lipsum[\inputlineno]
\begin{figure}[H]\centering
\LaTeX\TeX
\caption{another figure}
\end{figure}
\section{Second section}
\lipsum[\inputlineno]
\ignoreTable
\begin{table}[H]\centering
\TeX\LaTeX
\caption{my table}
\end{table}
\lipsum[\inputlineno]
\ignoreTable
\begin{table}[H]\centering
\TeX\TeX
\caption{another table}
\end{table}
\lipsum[\inputlineno]
\end{document}

Where if I write

\def\ignoreTable{\relax}
\def\ignoreFigure{\relax}

just after \begin{document} the output is:

---

Ideally, there would be an "elegant" macro or package, that would eliminate the list of tables, including its entry in the TOC, if there are not tables.

Answer 1

Here is another approach. What it does is to check at the end of the document the values of the figure and table counters, and add to the .aux file a boolean flag setting depending on whether these values are zero or positive.

Then you have on next run \iffigures and \iftables which allow you to act conditionally.

In the code below, perhaps the \global are not really needed, I didn't check.

See also a variant at bottom which does not use the figure/table counters because they might well be reset to zero due to document sectioning (as pointed out by egreg in a comment).

\documentclass[10pt,twocolumn]{article}
\usepackage{lipsum}
\usepackage[margin=0.75in]{geometry}
\usepackage{float}
\floatstyle{boxed}

\restylefloat{figure}
\restylefloat{table}

\newif\iffigures
\newif\iftables

\makeatletter
\AtEndDocument {%
    \if@filesw
       \ifnum\value{figure}=\z@ % no figures
          \immediate\write\@mainaux {\global\string\figuresfalse}%
       \else
          \immediate\write\@mainaux {\global\string\figurestrue}%
       \fi
       \ifnum\value{table}=\z@ % no tables
          \immediate\write\@mainaux {\global\string\tablesfalse}%
       \else
          \immediate\write\@mainaux {\global\string\tablestrue}%
       \fi
    \fi
}
\makeatother 

% for the purpose of testing

% this will make a MWE without tables
\long\def\IGNORE #1\ENDIGNORE{}

% uncomment to make a MWE with tables
% \let\IGNORE\empty
% \let\ENDIGNORE\empty

\begin{document}

\tableofcontents

% 
\iffigures
   \addcontentsline{toc}{section}{List of Figures}
   \listoffigures
\fi

% 
\iftables
   \addcontentsline{toc}{section}{List of Table}
   \listoftables
\fi

\section{First section}
\lipsum[\inputlineno]
\begin{figure}[H]\centering
\LaTeX\LaTeX
\caption{my figure}
\end{figure}
\lipsum[\inputlineno]
\begin{figure}[H]\centering
\LaTeX\TeX
\caption{another figure}
\end{figure}
\section{Second section}
\lipsum[\inputlineno]
\IGNORE
\begin{table}[H]\centering
\TeX\LaTeX
\caption{my table}
\end{table}
\ENDIGNORE
\lipsum[\inputlineno]
\IGNORE
\begin{table}[H]\centering
\TeX\TeX
\caption{another table}
\end{table}
\ENDIGNORE
\lipsum[\inputlineno]
\end{document}

Here is for a document with figures but no tables:

And if tables are present:

Three compilations needed.

Variant. I don't know to what extent patching \figure and \table as here is OK, depends perhaps on float related packages. At the worst I guess doing the patches immediately after \begin{document} should be enough (at the end of preamble might not be enough if some package does stuff during At Begin Document).

\documentclass[10pt,twocolumn]{article}
\usepackage{lipsum}
\usepackage[margin=0.75in]{geometry}
\usepackage{float}
\floatstyle{boxed}

\restylefloat{figure}
\restylefloat{table}

\newif\iffigures
\newif\iftables

\makeatletter

\let\OLDfigure\figure
\def\figure {\figures@in@document\OLDfigure }
\let\OLDtable\table
\def\table  {\tables@in@document\OLDtable }

\def\figures@in@document {%
    \immediate\write\@mainaux {\global\string\figurestrue}%
    \global\let\figures@in@document\empty
}

\def\tables@in@document {%
    \immediate\write\@mainaux {\global\string\tablestrue}%
    \global\let\tables@in@document\empty
}

\makeatother

% for the purpose of testing

% this will make a MWE without tables
\long\def\IGNORE #1\ENDIGNORE{}

% uncomment to make a MWE with tables
%\let\IGNORE\empty
%\let\ENDIGNORE\empty

\begin{document}

\tableofcontents

% 
\iffigures
   \addcontentsline{toc}{section}{List of Figures}
   \listoffigures
\fi

% 
\iftables
   \addcontentsline{toc}{section}{List of Table}
   \listoftables
\fi

\section{First section}
\lipsum[\inputlineno]
\begin{figure}[H]\centering
\LaTeX\LaTeX
\caption{my figure}
\end{figure}
\lipsum[\inputlineno]
\begin{figure}[H]\centering
\LaTeX\TeX
\caption{another figure}
\end{figure}
\section{Second section}
\lipsum[\inputlineno]
\IGNORE
\begin{table}[H]\centering
\TeX\LaTeX
\caption{my table}
\end{table}
\ENDIGNORE
\lipsum[\inputlineno]
\IGNORE
\begin{table}[H]\centering
\TeX\TeX
\caption{another table}
\end{table}
\ENDIGNORE
\lipsum[\inputlineno]
\end{document}

Answer 2

In order to add the lists to the table of contents, I recommend using tocbibind, which ensures correct page numbers even if the lists go on for more than one page.

The trick is to measure the contents of the .lof or .lot files: if they don't produce any output, we omit them, but we still initiate their production.

\documentclass[10pt,twocolumn]{article}
\usepackage{lipsum}
\usepackage[margin=0.75in]{geometry}
\usepackage{float}
\usepackage[nottoc]{tocbibind}
\floatstyle{boxed}


\restylefloat{figure}
\restylefloat{table}

\def\ignoreTable#1\end{table}{}
\def\ignoreFigure#1\end{figure}{}
%\def\ignoreTable{}
%\def\ignoreFigure{}

\makeatletter
\let\tocbibind@tocfile\tocfile
\renewcommand{\tocfile}[2]{%
  \setbox\z@=\vbox{\@input{\jobname.#2}}
  \ifdim\ht\z@>\z@
    \tocbibind@tocfile{#1}{#2}%
  \else
    % do the same as \@starttoc without the \@input instruction
    \begingroup
    \makeatletter
    \if@filesw
      \expandafter\newwrite\csname tf@#2\endcsname
      \immediate\openout \csname tf@#2\endcsname \jobname.#2\relax
    \fi
    \@nobreakfalse
    \endgroup
  \fi
}
\makeatother


\begin{document}

\tableofcontents
\listoffigures
\listoftables

\section{First section}
\lipsum[\inputlineno]
\ignoreFigure
\begin{figure}[H]\centering
\LaTeX\LaTeX
\caption{my figure}
\end{figure}
\lipsum[\inputlineno]
\ignoreFigure
\begin{figure}[H]\centering
\LaTeX\TeX
\caption{another figure}
\end{figure}
\section{Second section}
\lipsum[\inputlineno]
\ignoreTable
\begin{table}[H]\centering
\TeX\LaTeX
\caption{my table}
\end{table}
\lipsum[\inputlineno]
\ignoreTable
\begin{table}[H]\centering
\TeX\TeX
\caption{another table}
\end{table}
\lipsum[\inputlineno]
\end{document}

With the uncommented definitions of \ignoreTable and \ignoreFigure we get none of them and the output is

If I enable figures but not tables, the output is

Finally, if I enable tables and figures, I get

---

Alternative method

With an up-to-date TeX distribution, the assoccnt package is available and a much safer test can be used using it along with totcount.

Change the code above into

\documentclass[10pt,twocolumn]{article}
\usepackage{lipsum}
\usepackage[margin=0.75in]{geometry}
\usepackage{float}
\usepackage[nottoc]{tocbibind}
\floatstyle{boxed}

\usepackage{totcount,assoccnt}
\newtotcounter{totallof}
\newtotcounter{totallot}
\DeclareAssociatedCounters{figure}{totallof}
\DeclareAssociatedCounters{table}{totallot}

\restylefloat{figure}
\restylefloat{table}

\def\ignoreTable#1\end{table}{}
\def\ignoreFigure#1\end{figure}{}
%\def\ignoreTable{}
%\def\ignoreFigure{}

\makeatletter
\let\tocbibind@tocfile\tocfile
\renewcommand{\tocfile}[2]{%
  \ifnum\totvalue{total#2}>\z@ % there are figures or tables
    \tocbibind@tocfile{#1}{#2}%
  \else
    % do the same as \@starttoc without the \@input instruction
    \begingroup
    \makeatletter
    \if@filesw
      \expandafter\newwrite\csname tf@#2\endcsname
      \immediate\openout \csname tf@#2\endcsname \jobname.#2\relax
    \fi
    \@nobreakfalse
    \endgroup
  \fi
}
\makeatother


\begin{document}

\tableofcontents
\listoffigures
\listoftables

\section{First section}
\lipsum[\inputlineno]
\ignoreFigure
\begin{figure}[H]\centering
\LaTeX\LaTeX
\caption{my figure}
\end{figure}
\lipsum[\inputlineno]
\ignoreFigure
\begin{figure}[H]\centering
\LaTeX\TeX
\caption{another figure}
\end{figure}
\section{Second section}
\lipsum[\inputlineno]
\ignoreTable
\begin{table}[H]\centering
\TeX\LaTeX
\caption{my table}
\end{table}
\lipsum[\inputlineno]
\ignoreTable
\begin{table}[H]\centering
\TeX\TeX
\caption{another table}
\end{table}
\lipsum[\inputlineno]
\end{document}

Answer 3

You can measure the lists and discard them if they only have a heading:

\documentclass[10pt,twocolumn]{article}
\usepackage{lipsum}
\usepackage[margin=0.75in]{geometry}
\usepackage{float}
\floatstyle{boxed}

\def\wheninteresting#1{%
\setbox0\vbox{#1}%
\ifdim\ht0>35pt
\unvbox0
\fi}

\restylefloat{figure}
\restylefloat{table}

\def\ignoreTable#1\end{table}{}
\def\ignoreFigure#1\end{figure}{}
\begin{document}

\tableofcontents
\wheninteresting{
\addcontentsline{toc}{section}{List of Figures}
\listoffigures
}

\wheninteresting{
\addcontentsline{toc}{section}{List of Table}
\listoftables
}
\section{First section}
\lipsum[\inputlineno]
\ignoreFigure
\begin{figure}[H]\centering
\LaTeX\LaTeX
\caption{my figure}
\end{figure}
\lipsum[\inputlineno]
\begin{figure}[H]\centering
\LaTeX\TeX
\caption{another figure}
\end{figure}
\section{Second section}
\lipsum[\inputlineno]
\ignoreTable
\begin{table}[H]\centering
\TeX\LaTeX
\caption{my table}
\end{table}
\lipsum[\inputlineno]
\ignoreTable
\begin{table}[H]\centering
\TeX\TeX
\caption{another table}
\end{table}
\lipsum[\inputlineno]
\end{document}