How can I draw a diagonal that on one side, says Ratings and on the other, books?

This is an example made by @Marmot:

\documentclass{article}
\usepackage{amsmath,blkarray}

\begin{document}

$\begin{blockarray}{lccc} \text{Ratings} & \text{book}_1 & \text{book}_2 & \text{book}_3 \\ \begin{block}{l(ccc)} \text{user}_1 & - & 1 & - \smash[b]{\vphantom{\Big|}}\\ \text{user}_2 & - & 5 & - \\ \text{user}_3 & 4 & - & - \\ \text{user}_4 & - & - & 2\smash[t]{\vphantom{\Big|}}\\ \end{block} \end{blockarray}$
\end{document}


Desired output:

• Could you please add a sketch of the desired output to your question? Aslo how is the question related to tikz-pgf (which you chose as a tag for your question)? Lastly, you might be interested in Diagonally divided table cell or Diagonal lines in table cell – leandriis Jul 6 at 9:47
• I was told that it could be done with tikz so that it looks nicer. I have updated the OP. Nevermind the “movies’” label, Actually, what goes there is the word “books” – user192311 Jul 6 at 9:52

You can achieve the desired output using for example the slashbox package. In the following MWE I have aso included an alternative that might also be interesting:

\documentclass{article}
\usepackage{amsmath,blkarray}

%%%%% Only for the second example %%%%%
\usepackage{slashbox}
\usepackage{array,multirow,graphicx}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\begin{document}

$\begin{blockarray}{lccc} \text{\backslashbox{Ratings}{Books}} & \text{book}_1 & \text{book}_2 & \text{book}_3 \\ \begin{block}{l(ccc)} \text{user}_1 & - & 1 & - \smash[b]{\vphantom{\Big|}}\\ \text{user}_2 & - & 5 & - \\ \text{user}_3 & 4 & - & - \\ \text{user}_4 & - & - & 2\smash[t]{\vphantom{\Big|}}\\ \end{block} \end{blockarray}$

$\begin{blockarray}{llccc} & & \multicolumn{3}{c}{Books} \\ & & \text{book}_1 & \text{book}_2 & \text{book}_3 \\ \begin{block}{ll(ccc)} \parbox[t]{2mm}{\multirow{4}{*}{\rotatebox[origin=c]{90}{Rating}}} & \text{user}_1 & - & 1 & - \smash[b]{\vphantom{\Big|}}\\ & \text{user}_2 & - & 5 & - \\ & \text{user}_3 & 4 & - & - \\ & \text{user}_4 & - & - & 2\smash[t]{\vphantom{\Big|}}\\ \end{block} \end{blockarray}$

\end{document}

• Both look great. It’s gonna be hard to choose between them! – user192311 Jul 6 at 9:56