LaTeX Loop Statement: \foreach, \forloop, and \multido
Aug. 11, 2024
\foreach command
Example 1
Code source1
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\documentclass{standalone}
\usepackage{tikz,siunitx}
\begin{document}
\begin{tikzpicture}
\draw[->] (0,0) -- ({rad(210)}, 0);
\draw[->] (0,-1.2) -- (0,1.2);
\foreach \t in {0, 90, 180} {
\draw ({rad(\t)}, -0.05) -- ({rad(\t)}, 0.05);
\node[below, outer sep=2pt, fill=white, font=\small] at ({rad(\t)}, 0) {\ang{\t}};
}
\foreach \y in {-1,1} {\draw (-0.05,\y) -- (0.05,\y);}
\end{tikzpicture}
\end{document}
And a more complete version1
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\documentclass{standalone}
\usepackage{tikz,siunitx}
\begin{document}
\begin{tikzpicture}[scale=1.5]
\newcommand\iangle{120}
\begin{scope}[xshift=-2cm]
\draw[->] (-1.2,0) -- (1.2,0);
\draw[->] (0,-1.2) -- (0,1.2);
\draw[thick] (0,0) circle (1);
\coordinate[label=\iangle:$P$] (P) at (\iangle:1);
\coordinate[label=below:$P_0$] (P0) at (P |- 0,0);
\draw (0,0) -- (P);
\draw (P) -- (P0);
\fill[fill=gray,fill opacity=0.2]
(0,0) -- (0:1) arc (0:\iangle:1) -- cycle;
\filldraw[fill=gray,fill opacity=0.5]
(0,0) -- (0:0.3) arc (0:\iangle:0.3) -- cycle;
\node[right] at (\iangle/2:0.3) {\ang{\iangle}};
\end{scope}
\draw[->] (0,0) -- ({rad(210)}, 0);
\draw[->] (0,-1.2) -- (0,1.2);
\draw[thick, domain=0:rad(210)] plot (\x, {sin(\x r)})
node[right] {$\sin x$};
\foreach \t in {0, 90, 180} {
\draw ({rad(\t)}, -0.05) -- ({rad(\t)}, 0.05);
\node[below, outer sep=2pt, fill=white, font=\small] at ({rad(\t)}, 0) {\ang{\t}};
}
\foreach \y in {-1,1} {\draw (-0.05,\y) -- (0.05,\y);}
\coordinate[label=above:$Q$] (Q) at ({rad(\iangle)}, {sin(\iangle)});
\coordinate[label=below:$Q_0$] (Q0) at (Q |- 0,0);
\draw (Q) -- (Q0);
\draw[dashed] (P) -- (Q);
\end{tikzpicture}
\end{document}
siunitx package is “A comprehensive (SI) units package.”2
Example 2
Actually, \foreach command is provided by pgffor package, hence can be independent independent of tikz package1.
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\documentclass{standalone}
\usepackage{pgffor} % \usepackage{tikz}
\begin{document}
\foreach \i in {0,...,7}{
\i
}
\end{document}
Example 3
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\documentclass{standalone}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\foreach \i\j in {1/A,2/B,3/C,4/D,5/E,6/F}{
\node[draw,circle] at (\i,0){\Large\j};
}
\end{tikzpicture}
\end{document}
Example 4
Code source3
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\documentclass{standalone}
\usepackage[dvipsnames]{xcolor}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}[myNode/.style={circle,draw,fill=teal,text=white}]
\foreach \x in {0,...,4}
\foreach \y in {0,...,4}
\node [myNode] (\x\y) at (1.5*\x,1.5*\y) {\x,\y};
\foreach \x in {0,...,4}
\foreach \y [count=\yi] in {0,...,3}{
\draw[-latex] (\x\y)--(\x\yi);
\draw[-latex] (\y\x)--(\yi\x);
}
\foreach \x [count=\xi] in {0,...,3}
\foreach \y [count=\yi] in {0,...,3}
\draw[-latex] (\x\y)--(\xi\yi);
\end{tikzpicture}
\end{document}
Other examples
More exquisite TikZ design with \foreach can be found at TikZ examples feature: Foreach.
\forloop command
Example 1
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\documentclass{standalone}
\usepackage{forloop}
\begin{document}
\newcounter{x}
\forloop{x}{1}{\value{x} < 10}{
\arabic{x}
}
\end{document}
Example 2
Code source3
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\documentclass[varwidth]{standalone}
\usepackage{forloop}
\begin{document}
\newcounter{x}
\newcounter{y}
\forloop{y}{0}{\value{y} < 5}{
\forloop{x}{0}{\value{x} < 10}{
(\arabic{x},\arabic{y})
}
\\
}
\end{document}
Example 3
Code source3
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\documentclass{standalone}
\usepackage{forloop}
\usepackage{calc}
\begin{document}
\newcounter{x}
\newcounter{y}
\newcounter{z}
\begin{tabular}{||r||r|r|r|r|r|r|r|r|r|r||}
\hline\hline
\ & %skip the top left cell
\forloop{x}{0}{\value{x} < 10}{ % generates the header row of the table
\arabic{x} \ifthenelse{\value{x}<9}{&}{}
% one less '&' than the number of columns
}
\\\hline\hline
\forloop{y}{0}{\value{y} < 10}{
\arabic{y} \ifthenelse{\value{y}<10}{&}{}
\forloop{x}{0}{\value{x} < 10}{
\setcounter{z}{\value{x}*\value{y}} % '*' needs the calc package
\arabic{z} \ifthenelse{\value{x}<9}{&}{}
}
\\\hline
}
&\multicolumn{10}{|c||}{Multiplication Table}\\\hline
\end{tabular}
\end{document}
\multido command
The general syntax for \multido is:
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\multido{variables}{repetitions}{stuff}
stuff is whatever you want repeated; it can be any balanced TeX input. repetitions is the number times stuff is repeated.
The first argument is the interesting one. variables is a comma-separated list of variable declarations. Each variable declaration is of the form:
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variable = initial value + increment
variable is a command sequence that can be used in stuff. It is initially set to initial value, and is then incremented by increment with each repetition.
Example 1
Code source5
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\documentclass{standalone}
\usepackage{multido}
\begin{document}
\setlength{\unitlength}{1cm}
\small
\begin{picture}(8,1)(0,-.5)
\put(0,0){\vector(1,0){8}}
\multido{\i=0+1,\n=0+0.25}{8}{%
\put(\i,-.1){\line(0,1){.2}}
\put(\i,-.2){\makebox(0,0)[t]{\n}}}
\end{picture}
\end{document}
Example 2
Code source5
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\documentclass[varwidth]{standalone}
\usepackage{multido}
\begin{document}
\multido{}{10}{\TeX\ }
\multido{\d=2pt+3pt}{5}{\d, }
\multido{\n=2+3}{10}{\n, }
\multido{\i=2+-3}{10}{\i, }
\multido{\r=2+3.05}{6}{\r, }
\multido{\n=2.00+-3.05}{8}{\n, }
\end{document}
References
-
CTAN: Package
siunitx, documentation: siunitx – A comprehensive (SI) units package. ˄ -
CTAN: Package
forloop, documentation: forloop.pdf. ˄ -
CTAN: Package
multido, documentation: multido-doc.dvi. ˄ ˄2