Alternating Axis Labeling between Left and Right Axis

Question

I'm using the following to label a MatrixPlot:

FrameTicks -> {{yticks, None}, {None, xticks}},

I'm labeling these ticks with text. It is impossible to get the graph to a reasonable size while maintaining legibility of the text all on a single axis.

So what I'm attempting to do is sub-divide my label list, alternating the label that goes to one of two tick expressions:

FrameTicks -> {{leftyticks, rightyticks}, {None, xticks}},

But I have no idea how to do that. As of right now I am sorting the labels alternatively by hand and pasting them in to 'leftyticks' and 'rightyticks'. There has got to be a faster way to drag a list from a file, split it in alternating sequence, and dump the products in to the two tick-label groups, right?

Answer 1

Assuming I've understood your question correctly, something like this will work:

labels = CharacterRange["a", "z"]; (* fake labels a, b, .. z *)
yticks = MapIndexed[{First@#2, #1} &, labels]; (* {{1, a}, {2, b}, ..} *)

leftyticks = yticks[[1 ;; -1 ;; 2]];
rightyticks = yticks[[2 ;; -1 ;; 2]];
MatrixPlot[RandomReal[1, {26, 26}], 
 FrameTicks -> {{leftyticks, rightyticks}, {None, None}}]

The main thing to note is that the yticks list has the form {{y₁, label₁},{y₂, label₂}, ..}. See the documentation for Ticks.