Matrix and counters out of the matrix in TikZ

Code:

\begin{tikzpicture}
\matrix[matrix of math nodes, anchor=south west,
nodes={
draw=red,
align=center,
inner sep=0pt,
text width=1cm - \pgflinewidth,
minimum size = 1cm - \pgflinewidth
}
]{
A & B & D & B & A & C & E & G & E & H & E & C & F & I & F & C & A \\
0 & 1 & 2 & 1 & 0 & 1 & 2 & 3 & 2 & 3 & 2 & 1 & 2 & 3 & 2 & 1 & 0 \\
};
\foreach \x in {0,...,16}
\node[align=center] at (\x+1,0) {\x};
\end{tikzpicture}

Output: How can I program LaTeX in order to have consecutive numbers out and below of the matrix corresponding the columns of the matrix? Like this: • – Ignasi Dec 15 '17 at 14:26

\documentclass{standalone}

\usepackage{tikz}
\usetikzlibrary{matrix}

\begin{document}

\begin{tikzpicture}
\matrix[matrix of math nodes, anchor=south west,
nodes={
draw=red,
align=center,
inner sep=0pt,
text width=1cm - \pgflinewidth,
minimum size = 1cm - \pgflinewidth
}
]{
A & B & D & B & A & C & E & G & E & H & E & C & F & I & F & C & A \\
0 & 1 & 2 & 1 & 0 & 1 & 2 & 3 & 2 & 3 & 2 & 1 & 2 & 3 & 2 & 1 & 0 \\
};
\foreach \x in {0,...,16}
\node[align=center] at (\x+0.62,-0.04) {\x};
\end{tikzpicture}

\end{document} • You can also use \foreach \x in {1,...,17}\node[below= of n-1-\x] {\number\numexpr\x-1}; if you call the matrix node (n) and use positioning library. – percusse Dec 15 '17 at 13:30
• @percusse Thank you! one line to solve the problem! Can you explain the command \number\numexpr please? – Andrea Leo Dec 15 '17 at 15:59
• @AndreaLeo They are eTeX primitives to do simple math on-the-fly which TeX doesn't do. tex.stackexchange.com/questions/88344/… . For \number just use \the\numexpr as you would do with counters. It just fixes a technicality. – percusse Dec 15 '17 at 16:33

without matrix, shorter, simpler ?

\documentclass[tikz, margin=3mm]{standalone}
\usetikzlibrary{chains, positioning}

\begin{document}
\begin{tikzpicture}[
node distance = 0pt,
start chain = going right,
box/.style = {draw=red, minimum size=10mm, outer sep=0pt}
]
\foreach \i/\j [count =\k from 0] in {
A/0, B/1, D/2, B/1, A/0, C/1, E/2, G/3,
E/2, H/3, E/2, C/1, F/2, I/3, F/2, C/1,
A/0}
{
\node (n\k) [box,on chain] {\i};
\node [box, below=of n\k, label={[text=gray]below:\k}] {\j};
}
\end{tikzpicture}
\end{document} Another solution which automatically writes the column labels below the last row elements.

\documentclass{standalone}

\usepackage{tikz}
\usetikzlibrary{matrix}

\begin{document}

\begin{tikzpicture}
\matrix[matrix of math nodes, anchor=south west,
column sep=-\pgflinewidth,
row sep=-\pgflinewidth,
nodes={
draw=red,
align=center,
outer sep=0pt,
inner sep=0pt,
text width=1cm,
minimum size = 1cm
},
row 2/.style={execute at begin cell={%
|[label={[minimum size=6mm]below:\the\numexpr\pgfmatrixcurrentcolumn-1}]|},}
]{
A & B & D & B & A & C & E & G & E & H & E & C & F & I & F & C & A \\
0 & 1 & 2 & 1 & 0 & 1 & 2 & 3 & 2 & 3 & 2 & 1 & 2 & 3 & 2 & 1 & 0 \\
};
\end{tikzpicture}
\end{document} • Great idea! Very useful. – CarLaTeX Dec 18 '17 at 8:59
• @CarLaTeX. Thank you, but I had some external help ;-) – Ignasi Dec 18 '17 at 9:41
• (+1) This one must be the accepted one! – Cragfelt Dec 18 '17 at 15:56

A very simple one \documentclass[tikz]{standalone}
\usetikzlibrary{matrix}

\begin{document}

\begin{tikzpicture}
\matrix[matrix of math nodes, anchor=south west,
nodes={
draw=red,
align=center,
inner sep=0pt,
text width=1cm - \pgflinewidth,
minimum size = 1cm - \pgflinewidth
}
]{
A & B & D & B & A & C & E & G & E & H & E & C & F & I & F & C & A \\
0 & 1 & 2 & 1 & 0 & 1 & 2 & 3 & 2 & 3 & 2 & 1 & 2 & 3 & 2 & 1 & 0 \\
};
\foreach \x in {0,...,16}
\node[%
gray,
anchor=north east,
align=center,
text width=\pgflinewidth,
minimum size = 1cm - \pgflinewidth
]%
at (\x+1,0) {\x};

\end{tikzpicture}
\end{document}
• Thank for your time! PERCUSSE solve the problem in one line! – Andrea Leo Dec 15 '17 at 16:08

The idea of this solution is to put the numbers into the third row of the matrix. But since I don't want to drop the loop, the solution becomes more complicated then expected.

First, I make sure that nodes are drawn with borders only for the first two rows, hence the [cell/.style] option and [row 1/.style]-[row 3/.style].

Second, following an answer in Tikz foreach inside matrix I collect the numbers from 0 to 16 into a macro \mymatrixcontents and use it as the third matrix row. The \catcode command is necessary because without it PGF issues an error (alternatively, you might replace & by, say, \& and use option ampersand replacement=\&).

The code:

\documentclass{article}
\usepackage[landscape]{geometry}
\usepackage{tikz}
\usetikzlibrary{matrix}
\usepackage{etoolbox}
\begin{document}
\begin{tikzpicture}[cell/.style={align=center,inner sep=0pt,text width=1cm,minimum size=1cm}]
\let\mymatrixcontent\empty
\catcode`\&=\active
\foreach \x in {0,...,16} {%
\expandafter\gappto\expandafter\mymatrixcontent\expandafter{\x &}%
}
\gappto\mymatrixcontent{\\}
\tikzstyle{row 3}=[gray,draw=white]
\matrix[matrix of math nodes, anchor=south west,
row 1/.style={nodes={cell,draw=red}},
row 2/.style={nodes={cell,draw=red}},
row 3/.style={nodes={cell,gray}}
]{
A & B & D & B & A & C & E & G & E & H & E & C & F & I & F & C & A \\
0 & 1 & 2 & 1 & 0 & 1 & 2 & 3 & 2 & 3 & 2 & 1 & 2 & 3 & 2 & 1 & 0 \\
\mymatrixcontent
};
\end{tikzpicture}
\end{document}

The output: • TThank for your time! PERCUSSE solve the problem in one line! – Andrea Leo Dec 15 '17 at 16:08
• You should add row sep=-\pgflinewidth, column sep=-\pgflinewidth to avoid thick lines between the cells. – CarLaTeX Dec 15 '17 at 19:10