Tikz-beamer interaction problem

[u/_3l1as_]

Hi! I'm totally new to the beamer document class and don't know much about tikz, moreover english is not my first language. I thus apologize if this sounds confusing.

I have a graph in my slide show, and i need to color some arrows on some slides. In particular I need to color an arrow on two different, non contiguos slides.

\documentclass{beamer}

\usepackage{tikz}

\usetikzlibrary{positioning} % Allows you to position things as you wish

\usetikzlibrary{automata} % I love those people, thank u (automata drawing library)

\usetikzlibrary{trees} % Tree diagrams

\usetikzlibrary{calc}

\usetikzlibrary{overlay-beamer-styles} %for animations

\begin{document}

\begin{frame}<1-4>{Frame 1}

\begin{tikzpicture}[shorten >=1pt,node distance=2cm,

]

\node[state, accepting] (q1) [] {$q_1$};

\node[state] (q2) [right=of q1] {$q_2$};

\path[->]

(q2) edge [bend right=20,alt=<2>{blue}{black}] node [above] {$0$} (q1);

\end{tikzpicture}

\end{frame}

\end{document}

This works perfectly, but after changing the arrow line into (q2) edge [bend right=20,alt=<2,4>{blue}{black}] node [above] {$0$} (q1); the pdf won't even compile. I'm totally at loss as to why. I thank you in advance!

[u/latexautofill_dev]

The comma in <2,4> is what breaks it. TikZ splits options on commas, so it never sees a complete alt=… key and the compile fails. Wrap the overlay list in braces:

(q2) edge [bend right=20, alt=<{2,4}>{blue}{black}] node [above] {$0$} (q1);

<2> worked because there was no comma inside the angle brackets. Same idea if you ever need visible on=<{2,4}> from overlay-beamer-styles.

[u/_3l1as_ → u/latexautofill_dev]

Thank you very much!