How to get position of single box in grouped box chart on x-axis?

I would like to get the position of each single box on the x-axis I created with boxchart(). But the box chart object is grouped, so when I type XAxis.Categories I only get the two grouping categories even though it's actually 6 boxes.

Answer 1

[Scott MacKenzie]

The use of grouped data changes the XData type to categorical for the BoxChart. Plus, there doesn't seem to be any BoxChart property that gives the x position of the group or the x-offset of the boxes within a group. I determined that the actual x positions of the groups are 1, 2, 3, etc., as they would be if the data were not categorical. Knowing this, I concocted a scheme to compute the x-position of each box, so that text annotations (or whatever) can be added. See below. This can probably be vectorized in some way, but I thought it might useful to post this in the present form.

set(groot, 'defaultTextHorizontalAlignment', 'center');
m = 3; % number of boxes per group
xGap = 1 / m;

grp = 1; % x position for 1st group
text(grp-xGap, 30, 'a1');
text(grp, 30, 'a2');
text(grp+xGap, 30, 'a3');

grp = 2; % x position for 2nd group
text(grp-xGap, 30, 'b1');
text(grp, 30, 'b2');
text(grp+xGap, 30, 'b3');