Controlling format (number of decimals) of specific ticks

I have a y axis running from 0 to 1 in the form of 0, 0.1, 0.2...1. I want to add an extra label, rounded to 3 decimals. By default, it's doing 4 decimals. The usual one liner to control decimals,

set(gca,'yticklabel',num2str(get(gca,'ytick')','%.3f'))

is doing it for all the points and making it ugly such as 0.100, 0.200...1.000. I just want the specific tick to have 3 decimals, not all of them. Is this possible?

Answer 1

[dpb]

figure
hAx=axes;
xtklab=get(hAx,'xticklabel');
xtklab{1}='0.000';
set(hAx,'xticklabel',xtklab)

results in

where just made arbitrary change. Obviously you can retrieve the actual tick values and convert them if don't know the actual value.

If you want to add another tick besides the default, you'll have to create those first then create the correct number of labels to match formatting them on a per each basis with the proper format string, then update.

Again, if it's known which one, doing the modification of the ticks themselves and letting the automagic labels be written first makes sense; after that just follow the above template to adjust just the one in the array wherever it is positioned.

The new axis ruler property has a 'Format' property, but it's global for the axis, not on a per tick basis.

ADDENDUM

So, for the given case...

NewTickVal=0.355;               % the desired new tick value
hAx=axes;
ytk=sort([NewTickVal hAx.YTick]); % put it in the right place
hAx.YTick=ytk;                  % and update the tick positions
ytklab=hAx.YTickLabel;          % get the new labels array        
iy=find(ytk==NewTickVal);       % find the one we want
ytklab{iy}=num2str(ytk(iy),'%.3f');  % and write in desired fmt
hAx.YTickLabel=ytklab;          % reset labels array

The key thing to remember with tick labels vis a vis ticks is that they are NOT connected in any way whatsoever except by positional order. The label array is simply associated 1:1 in sequential order to the tick array position.

This also illustrates the use where it's convenient of the dot nomenclature for retrieving/setting properties. NB: with it, capitalization is significant where it is not with get set

[bloodtalon]

But my label is a variable so that's not working. Something more like %.3f is what I am expecting. Unless you have a way to convert the double to a 3 d.p. string...

[dpb]

Of course "it's working". :) The point illustrated is to modify one (or perhaps more) of the given label string array. You'd already demonstrated you knew how to convert an array of variables to the desired format; it didn't seem that there was any challenge to do only one.

The ? raised is you just have to know which value it is you're after--which your description is ambiguous over so I asked whether you mean a specific tick of existing tick array or what the "extra" above refers to so could write more specific code.

[bloodtalon]

So it is an extra tick at 0.355 between 0.3 and 0.4. Also, the extra tick is on the y axis, not the x for me. I added this line but it's screwing everything up pretty badly for some reason. Any suggestions?

hAx=axes; 
ytklab=get(hAx,'yticklabel'); ytklab{1}=num2str(y(1));
set(hAx,'yticklabel',ytklab)

[dpb]

Yeah, as noted, to add one (or more) you've got to add the tick values first else't there's nowhere to put the labels.

[bloodtalon]

Before and after running that code

[bloodtalon]

If by adding first you mean this, I get the same result. Could you clarify?

extick = round(y(1),3,'significant');
hAx=axes;
ytklab{1}=num2str(extick);
ytklab=get(hAx,'YTickLabel');
set(hAx,'YTickLabel',ytklab)

By the way the previous code which gave it to 4 dp but worked was

set(gca, 'YTick', sort([y(1), get(gca, 'YTick')]));

[bloodtalon]

OK so that mess was due to the axes for some reason. This code is working for the most part, except replacing my 1st value since I have {1}.

extick = round(y(1),3,'significant');
a=gca;
ytklab=get(a,'YTickLabel');
ytklab{1}=num2str(extick);
set(a,'YTickLabel',ytklab)

[dpb]

None of the above except the one I had done before ever actually added the additional tick you're trying to label...the ticks must exist before you can put labels on them (seems obvious said that way?).