# Loopy LaTeX

Something that you may or may not know, is that you can write loops in LaTeX. It is, in fact, a Turing-complete language, so you can write if statements too (which is helpful for making multi-line comments), and do all the other things you can do with a programming language.

So, I guess you are thinking, ‘eh, that’s cool, but why would I do it?’ Indeed, I have known about this for ages, but never found any need for it, until recently. My problem was that I had generated 80 small images, that I wanted to display on a number of pages. I could have played with print settings, and made multiple pages per sheet, but since I wanted two columns, and to fit 16 to a page (the 80 images were in 5 sets of 16, each with two subsets), that was going to be a pain. I also wanted to add some labels to each set, but not have said label on every image. However, I thought that LaTeX could solve my problem.

As ever, there are a number of different latex packages that you can use, but I used the pgffor package. In the example below, my pictures were named [A-E]_[ab][1-8]_picture, e.g. A_b2_picture.png, or D_a3_picture.png. The code produces pages of 16 pictures, with the ‘a’ pictures on the left, and the ‘b’ pictures on the right.
There is a more simple example at the bottom.

\documentclass[a4paper,10pt]{article}
\usepackage[utf8]{inputenc}
\usepackage{pgffor}
\usepackage{subfigure}
\usepackage{graphicx}
\usepackage{caption}
\usepackage{subcaption}
\usepackage{fullpage}

\begin{document}
\section{}

\foreach \method in {A, B, C, D, E}{ %looping over each set of 16
\begin{figure}
\foreach \i in {1,...,8}{ %looping over each subset, the a set first, then the b set
\centering
\subfigure[]{\label{fig:\method \i a}\includegraphics[width=0.45\textwidth]{\method _a\i _picture}}
\subfigure[]{\label{fig:\method \i b}\includegraphics[width=0.45\textwidth]{\method _b\i _picture}}
}
\caption{\method}
\end{figure}
}

%a more simple example
\foreach \number in {1,...,10}{
\number \ elephant
}

\end{document}

Happy LaTeXing..