[Tex/LaTex] Drawing Grid Lines using \foreach

foreachtikz-pgf

I am trying to draw gridlines inside a square. Here is my code:

\documentclass{article}
\usepackage{pgfplots}
\pgfplotsset{compat=1.15}

\begin{document}

\begin{figure}[ht]

\centering

\begin{tikzpicture}[scale=1.25,line width=1pt]
\begin{axis}[
color= white,
xmin=-28.9, 
xmax=28.9, 
ymin=-28.9, 
ymax=28.9, 
axis equal image, 
axis lines=middle,
]

\foreach \x in {-24,..., 24}
    {\draw[thin, gray] (\x,-24) -- (\x,24);}

\draw[black, thin] (-24,-24) -- (-24,24) -- (24,24) -- (24, -24) -- 
(-24,-24);

\node[black, below] at (24,-24) {$(1,0)$};

\node[black, below] at (-24,-24) {$(0,0)$};

\node[black, above] at (-24,24) {$(0,1)$};

\node[black, above] at (24,24) {$(1,1)$};

\end{axis}
\end{tikzpicture}

\end{figure}

\end{document}

This code, however, will not compile. My goal is to make a square with a 24 x 24 grid.

Best Answer

Works fine if you use \pgfplotsinvokeforeach instead of \foreach:

Notes:

I would suggest you try the grid options built into pgfplots and tikz.
All the code you showing does not require pgfplots so you can eliminate the axis environment. So, unless there is other functionality that is not shown in the MWE, you should consider the non-axis environment version which uses \foreach.

References:

Code: `pgfplots`

\documentclass{article}
\usepackage{pgfplots}
\pgfplotsset{compat=1.15}

\begin{document}
%
%\begin{figure}[ht]
%
%\centering
%
\begin{tikzpicture}%[scale=1.25,line width=1pt]
\begin{axis}[
    color= white,
    xmin=-28.9, 
    xmax=28.9, 
    ymin=-28.9, 
    ymax=28.9, 
    axis equal image, 
    axis lines=middle,
]

\pgfplotsinvokeforeach {-24,...,24} {%
    \draw[thin, gray] (#1,-24) -- (#1,24);
}

\draw[black, thin] (-24,-24) -- (-24,24) -- (24,24) -- (24, -24) -- 
(-24,-24);

\node[black, below] at (24,-24) {$(1,0)$};

\node[black, below] at (-24,-24) {$(0,0)$};

\node[black, above] at (-24,24) {$(0,1)$};

\node[black, above] at (24,24) {$(1,1)$};

\end{axis}
\end{tikzpicture}%
%
%\end{figure}
%
\end{document}

Code: no `pgfplots`

\documentclass{article}
\usepackage{pgfplots}
\pgfplotsset{compat=1.15}

\begin{document}
\begin{tikzpicture}[scale=0.10]

\foreach \x in  {-24,...,24} {%
    \draw[thin, gray] (\x,-24) -- (\x,24);
}

\draw[black, thin] (-24,-24) -- (-24,24) -- (24,24) -- (24, -24) -- 
(-24,-24);

\node[black, below] at (24,-24) {$(1,0)$};

\node[black, below] at (-24,-24) {$(0,0)$};

\node[black, above] at (-24,24) {$(0,1)$};

\node[black, above] at (24,24) {$(1,1)$};

\end{tikzpicture}%
\end{document}

Output

Code

\documentclass[margin=10pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{positioning}

\begin{document}
\begin{tikzpicture}

\node[draw, rectangle] (n0) {0};
\foreach \x [remember=\x as \lastx (initially 0)] in {1,...,4}{
    \node [draw, rectangle, right =of n\lastx] (n\x) {\x};
}
\end{tikzpicture}
\end{document}

[Tex/LaTex] Line up nested tikz enviroments or how to get rid of them

As is explained in How do I draw shapes inside a tikz node? pics can be used for defining new objects. My main problem using pics is how to place where you want because they aren't nodes and positioning them is not so easy.

Following code shows how to define EDFA block.

    EDFA/.pic={
        \begin{scope}[scale=.5]
        \draw (-1,0) coordinate (in) --  (-1,1) -- (1,0) coordinate (out) --  (-1,-1) -- cycle;
        \node[anchor=north,inner sep=2pt] at (0,-1) {$1$};
        \end{scope}

In this case, coordinate (-1,0) will act as west anchor and 1,0 as east. Both point will have an special name for further reference. Every pic is placed according its own origin (0,0). You can use Claudio's answer to Anchoring TiKZ pics for better positioning.

As your example was simple, I'd prefer to star with EDFA and place Source and Sink after it.

\documentclass[]{article}

% tikz
\usepackage{tikz}
\usetikzlibrary{positioning} %relative positioning

\begin{document}

\tikzset{%
    EDFA/.pic={
        \begin{scope}[scale=.5]
        \draw (-1,0) coordinate (in) --  (-1,1) -- (1,0) coordinate (out) --  (-1,-1) -- cycle;
        \node[anchor=north,inner sep=2pt] at (0,-1) {$1$};
        \end{scope}
    }
}

\begin{tikzpicture}[
block/.style={draw},
]

\draw pic (edfa) {EDFA};

\node[block, left=of edfain] (source) {Source};

\node[block, right= of edfaout] (sink) {Sink};

\draw[->] (source) -- (edfain);
\draw[->] (edfaout) -- (sink);

\end{tikzpicture}

\end{document}

I understand that your components are more complex than EDFA because for this particular case an isosceles triangle node with a label will do the work and it can be used as a node and not as a pic:

\documentclass[]{article}

% tikz
\usepackage{tikz}
\usetikzlibrary{positioning} %relative positioning
\usetikzlibrary{shapes.geometric}

\begin{document}

\begin{tikzpicture}[
    block/.style={draw},
    edfa/.style={isosceles triangle, minimum width=1cm, 
         draw, anchor=west, isosceles triangle stretches, 
         minimum height=1cm, label=-80:#1}
]

\node[block] (source) {Source};

\node[edfa=1, right=of source] (edfa) {};

\node[block, right= of edfa] (sink) {Sink};

\draw[->] (source) -- (edfa);
\draw[->] (edfa) -- (sink);

\end{tikzpicture}

\end{document}

Best Answer

Notes:

References:

Code: pgfplots

Code: no pgfplots

Related Solutions

[Tex/LaTex] Drawing an array of nodes using the foreach-construct

Output

Code

[Tex/LaTex] Line up nested tikz enviroments or how to get rid of them

Related Question

Code: `pgfplots`

Code: no `pgfplots`