How to draw a separator between the columns of a matrix.

Question

Is there a simple way to tell TikZ that I want a vertical line to separate the columns of a matrix? I know how to draw them manually, I am looking for an automatic solution, maybe using styles or something.

Answer 1

You can use "matrix of nodes" and anchors:

\begin{tikzpicture}
\matrix (mat) [matrix of nodes]
 {
  1 & 2 & 3 \\
  1 & 2 & 3 \\
  1 & 2 & 3 \\
  1 & 2 & 3 \\
 };
% Matrix is called 'mat' first number is row, second numer is column
\draw[thick,red] (mat-1-1.north east) -- (mat-4-1.south east);
\end{tikzpicture}

Answer 2

Here's an example with a matrix of math nodes, with delimiters and a separation line with some shifting for that.

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{matrix}
\begin{document}
\begin{tikzpicture}
\matrix (m) [matrix of math nodes,left delimiter=(,right delimiter=),
  inner sep=2pt,outer sep=0pt]{
  a & b & [1em] 0 \\
  c & d & 1 \\ };
\draw ([xshift=0.5em]m-1-2.north east) -- ([xshift=0.5em]m-2-2.south east);
\end{tikzpicture}
\end{document}

If the entries would have different width, you could use |- instead of -- to get straight lines, such as

\draw ([xshift=0.5em]m-1-2.north east-|m-2-2.south east) -|
      ([xshift=0.5em]m-2-2.south east);

Even better: set the minimum width property for the nodes in the matrix.

Answer 3

Here's an answer based on answers given at Obstacles to simulating an amsmath matrix by a TiKZ matrix of math nodes and How can I set the background color of the rows and columns of a matrix node in Tikz? You don't specify in the question what type of matrix you are wanting to typeset, so I've simply gone for a similar matrix to that which Stefan and xeroc have used. Exactly what code you need depends a lot on what your matrix code looks like. The only one that you really need is the code from How can I set the background color of the rows and columns of a matrix node in Tikz? The others are there to make it look more impressive.

If the code from How can I set the background color of the rows and columns of a matrix node in Tikz? were in a package (below called tikzamsmatrix), the document would look like this:

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{matrix,decorations}
\usepackage{calligraphy}
\usepackage{matrixcells}
\usepackage{tikzamsmatrix}

\begin{document}
\[
\begin{tikzamatrix}
a & b & 0 \\
c & a + c & {\displaystyle \int_0^1 \sin(x) d x}
\end{tikzamatrix}
\]
\end{document}

and would produce:

Since that question isn't yet in a package, the code actually looks like this:

\documentclass{article}
%\url{https://tex.stackexchange.com/q/9492/86}
\usepackage{amsmath,tikz}
\usetikzlibrary{matrix,decorations}
\usepackage{calligraphy}
\usepackage{matrixcells}

\newlength\mtxrowsep
\setlength\mtxrowsep{1.5ex}
\newlength\mtxcolsep
\setlength\mtxcolsep{2\arraycolsep}

\makeatletter
\pgfdeclaredecoration{doubled lineto}{brace}
{
  \state{brace}[width=+\pgfdecoratedremainingdistance,next state=final]
  {
    \pgfsyssoftpath@setcurrentpath{\pgfutil@empty}
    \pgfpathmoveto{\pgfpointorigin}
    \pgfpathlineto{\pgfqpoint{\pgfdecoratedremainingdistance}{0pt}}
    \pgfpathmoveto{\pgfqpoint{0pt}{\pgfdecorationsegmentamplitude}}
    \pgfpathlineto{\pgfqpoint{\pgfdecoratedremainingdistance}{\pgfdecorationsegmentamplitude}}
  }
  \state{final}{}%
}
\pgfdeclaredecoration{bracket}{brace}
{
  \state{brace}[width=+\pgfdecoratedremainingdistance,next state=final]
  {
    \pgfsyssoftpath@setcurrentpath{\pgfutil@empty}
    \pgfpathmoveto{\pgfpointorigin}
    \pgfpathlineto{\pgfqpoint{0pt}{\pgfdecorationsegmentamplitude}}
    \pgfpathlineto{\pgfqpoint{\pgfdecoratedremainingdistance}{\pgfdecorationsegmentamplitude}}
    \pgfpathlineto{\pgfqpoint{\pgfdecoratedremainingdistance}{0pt}}
  }
  \state{final}{}%
}
\makeatother

\expandafter\def\csname delimiter \string\lbrace\endcsname{calligraphic brace}
\expandafter\def\csname delimiter \string(\endcsname{calligraphic curved parenthesis}
\expandafter\def\csname delimiter \string|\endcsname{lineto}
\expandafter\def\csname delimiter \string\|\endcsname{doubled lineto}
\expandafter\def\csname delimiter \string[\endcsname{bracket}
\expandafter\def\csname delimiter \string\rbrace\endcsname{calligraphic brace}
\expandafter\def\csname delimiter \string)\endcsname{calligraphic curved parenthesis}
\expandafter\def\csname delimiter \string]\endcsname{bracket}

\tikzset{
  ams/.style={
    baseline=-.7ex,
    every delimiter/.style={yshift=-1pt},
    every left delimiter/.style={xshift=2pt},
    every right delimiter/.style={xshift=-2pt},
    every node/.style={inner sep=0pt},
    execute at end picture={
      \path (current bounding box.east) ++(\pgfkeysvalueof{/tikz/ams matrix xsep},0) (current bounding box.west) ++(-\pgfkeysvalueof{/tikz/ams matrix xsep},0);
    },
  },
  ams matrix xsep/.initial={.5ex},
  ams matrix/.style={
    inner sep=1pt,
    column sep=\mtxcolsep,
    row sep=\mtxrowsep,
%    ampersand replacement=\&,
    matrix of math nodes,
  },
  ams delimiters/.style args={#1,#2}{
    left delimiter={#1},
    right delimiter={#2},
  },
  delimiters/.style args={#1,#2}{
    \pgfkeysvalueof{/tikz/matrix delimiter type} delimiters={{#1},{#2}},
  },
  matrix delimiter type/.initial={tikz},
  tikz delimiter style/.style={
    thick,
  },
  tikz delimiters/.style args={#1,#2}{
    left tikz delimiter={#1},
    right tikz delimiter={#2},
  },
  left tikz delimiter/.style={
    render left tikz delimiter/.expand once={\csname delimiter \string#1\endcsname}
  },
  render left tikz delimiter/.style={
    append after command={(\tikzlastnode.north west) edge[tikz delimiter style,decorate,decoration={mirror,#1}] (\tikzlastnode.south west)}
  },
  right tikz delimiter/.style={
    render right tikz delimiter/.expand once={\csname delimiter \string#1\endcsname}
  },
  render right tikz delimiter/.style={
    append after command={(\tikzlastnode.north east) edge[tikz delimiter style,decorate,decoration={#1}] (\tikzlastnode.south east)}
  },
  bmatrix/.style={
    ams,
    every matrix/.style={
      ams matrix,
      delimiters={[,]},
    }
  },
  Bmatrix/.style={
    ams,
    every matrix/.style={
      ams matrix,
      delimiters={\lbrace,\rbrace},
    }
  },
  pmatrix/.style={
    ams,
    every matrix/.style={
      ams matrix,
      delimiters={(,)},
    }
  },
  vmatrix/.style={
    ams,
    every matrix/.style={
      ams matrix,
      delimiters={|,|},
    }
  },
  Vmatrix/.style={
    ams,
    every matrix/.style={
      ams matrix,
      delimiters={\|,\|},
    }
  },
}

\let\matamp=&

\catcode`\&=13
\makeatletter
\def&{\iftikz@is@matrix
  \pgfmatrixnextcell
  \else
  \matamp
  \fi}
\makeatother

%\usepackage{environ}
\def\endtikzmatrix{\\\egroup;\end{tikzpicture}}
\foreach \mtype in {b,B,p,v,V} {

\expandafter\xdef\csname tikz\mtype matrix\endcsname{%
    \noexpand\begin{tikzpicture}[\mtype matrix,matrix delimiter type={tikz}]
    \noexpand\matrix \noexpand\bgroup}
\expandafter\xdef\csname ams\mtype matrix\endcsname{%
    \noexpand\begin{tikzpicture}[\mtype matrix,matrix delimiter type={ams}]
    \noexpand\matrix \noexpand\bgroup}
\expandafter\global\expandafter\let\csname endtikz\mtype matrix\endcsname=\endtikzmatrix
\expandafter\global\expandafter\let\csname endams\mtype matrix\endcsname=\endtikzmatrix
}

\def\tikzamatrix{\begin{tikzpicture}[pmatrix,matrix delimiter type={tikz}]\matrix[label cells,name=am]\bgroup}
\def\endtikzamatrix{\\\egroup;\draw (am-cell-1-\the\pgfmatrixcurrentcolumn.north west) -- (am-cell-\the\pgfmatrixcurrentrow-\the\pgfmatrixcurrentcolumn.south west);\end{tikzpicture}}

\begin{document}
\begin{tikzamatrix}
a & b & 0 \\
c & a + c & {\displaystyle \int_0^1 \sin(x) d x}
\end{tikzamatrix}
\end{document}

(The calligraphy and matrixcells package are available from TeX-SX launchpad page.)

Answer 4

Even if you ask for a TikZ solution, here is another way, with the nicematrix extension.

Thus, as pointed out by @Caramdir, lines are automatically adjusted, whatever you have in the matrix.

In addition you can use TikZ commands to tweak cells inside the matrix. Have a look at the documentation!

\documentclass{article}
\usepackage{nicematrix}
\DeclareRobustCommand{\dder}{\mathop{}\mathopen{}\mathrm{d}}
\begin{document}
  $\begin{pNiceArray}{c|c|c}
    1 & \int_{0}^{\infty}2x \dder x & 3 \\
    1 & 2 & 3 \\
    1 & 2+3+4 & 3 \\
    1 & 2 & 3 \\
  \end{pNiceArray}$
  
\end{document}