How to draw these images with TikZ?

Question

I had once the need to use these graphics:

It seemed to be a simple table, but I was not able to

draw randomly while crossing table lines, but with respect to the cell's coordinates (like in the first picture)
set an offset to distinguish the continuous line from the dotted line (second picture)

I do not have to use these graphics now, but I found that it annoyed me not knowing how to do this. I am sure one could draw them completely within TikZ, but perhaps it is possible to marry TikZ with a table to not being bothered with a complicated calculation of coordinates.

Could anyone give a hint or a solution? My TikZ knowledge is rather small and merely of theoretical nature.

Doing everything in TikZ is probably less fuzz than mixing in a tabular, a TikZ \matrix might be useful. As an addendum, I know the following isn't that helpful, but at a basic level the diagrams are quite simple. If you know how to draw a line between points and how to place text at a specified point, you can do the bulk of them, so a lot of TikZ knowledge isn't needed. (Of course, some knowledge could make it easier to do.) — Torbjørn T., Sep 28 '19 at 10:57
The first picture can be obtained e.g. with \documentclass[tikz,border=3mm]{standalone} \begin{document} \begin{tikzpicture} \draw (-2,1) -- (4.5,1) (-1,2) -- (-1,-4.5); \foreach \X [count=\Y starting from 0] in {\mu=0,1,2,3,\cdots} {\node[above=0.5ex] at (\Y,1) {$\X$};} \foreach \X [count=\Y starting from 0] in {\nu=0,1,2,3,\cdots} {\node[left=0.5ex] at (-1,-\Y) {$\X$};} \draw[mark=*] plot coordinates {(0,0) (1,0) (2,0) (2,-1) (3,-1) (3,-2) (4,-2) (4,-3)}; \end{tikzpicture} \end{document} ... — , Sep 28 '19 at 11:22
It's wonderful to now have two different approaches. Thanks! — user7427029, Sep 29 '19 at 15:14

score 10 · Accepted Answer · answered Sep 28 '19 at 11:23

Here is one possibility using a \matrix. There are some comments in the code, ask if anything is unclear.

\documentclass[border=5mm]{standalone}
\usepackage{tikz}
\usetikzlibrary{matrix}

% hack for style of empty cells from https://tex.stackexchange.com/a/386805/ 
\tikzset{empty node/.style={coordinate}}
\makeatletter
\def\tikz@lib@matrix@empty@cell{\iftikz@lib@matrix@empty\node[name=\tikzmatrixname-\the\pgfmatrixcurrentrow-\the\pgfmatrixcurrentcolumn,empty node]{};\fi}
\makeatother

\begin{document}
\begin{tikzpicture}

\matrix [
  % with the following option each cell becomes a node, set in math mode
   % the nodes are named automatically as <matrix name>-<row number>-<column number>
   matrix of math nodes, 
   nodes in empty cells, % add cells also to empty nodes
   nodes={minimum width=1cm, minimum height=1cm, font=\strut} % set style of nodes
] (m) % give the matrix the name m
{
 & \mu = 0 & 1 & 2 & 3 & \dots \\
\nu = 0 & & & & & \\
1 & & & & & \\
2 & & & & & \\
3 & & & & & \\
\vdots & & & & &  \\
};

% for explanation of |- syntax: https://tex.stackexchange.com/a/401429/
% used to ensure horizontal/vertical lines
\draw (m-1-2.north west) -- (m-1-2.north west |- m-6-1.south east);
\draw (m-2-1.north west) -- (m-2-1.north west -| m-1-6.south east);

% due to the automatic node naming mentioned above, m-1-2 is the
% node in the first row, second column of the matrix

% a plot is an easy way of drawing a line with dots
\draw plot[mark=*] coordinates {(m-2-2)(m-2-3)(m-2-4)(m-3-4)(m-3-5)};


% for explanation of |- syntax: https://tex.stackexchange.com/a/401429/
% using that you only need to specify every other corner on the path
\draw (m-3-2) |- (m-4-3) |- (m-6-6);

% draw shifted, dotted line
% transform canvas idea from https://tex.stackexchange.com/a/180669/ 
\draw [dotted, transform canvas={shift={(5pt,5pt)}}] (m-3-2) |- (m-4-3) |- (m-6-6);

\end{tikzpicture}
\end{document}

Very interesting. I did not even know that a matrix could have this kind of arguments. Thanks! — user7427029, Sep 29 '19 at 15:14

score 3 · Answer 2 · answered Aug 04 '23 at 06:41

With {NiceArray} of nicematrix and Tikz to draw the broken lines with the Tikz nodes created by nicematrix.

\documentclass{article}
\usepackage{nicematrix,tikz}
\begin{document}
[
\begin{NiceArray}{c|ccccc}
           & \mu = 0 & 1 & 2 & 3 & \cdots \
   \hline
   \nu = 0 \
   1       \
   2       \
   3       \
   \vdots

\CodeAfter
   \tikz [radius=2pt,every circle/.style = fill]
    \draw plot [mark = *] coordinates 
      {(2.5-|2.5)(2.5-|3.5)(2.5-|4.5)(3.5-|4.5)(3.5-|5.5)(4.5-|5.5)(4.5-|6.5)(5.5-|6.5)} ;
\end{NiceArray}
]
[
\begin{NiceArray}{c|ccccccc}
          & \mu = 0 & 1 & 2 & 3 & \cdot & \cdot & \cdot \
  \hline
  \nu = 0 \
  1       \
  2       \
  \cdot   \
  \cdot   \
  \cdot   \
\CodeAfter
  \begin{tikzpicture}
    \draw (2.5-|2.5) -- (2.5-|4.5) |- (3.5-|5.5) |- (4.5-|6.5) |- (5.5-|7.5) ; 
    \draw (2.5-|2.5) -- (5.5-|2.5) -| (6.5-|3.5) -| (7.5-|4.5) ; 
    \draw [dotted] 
          ([xshift=1mm]2.5-|2.5) |- (3.5-|3.5) |- (4.5-|4.5) |- (5.5-|5.5) |- (6.5-|6.5) ; 
  \end{tikzpicture}
\end{NiceArray}
]
\end{document}

How to draw these images with TikZ?

2 Answers2

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