Set specific date ticks

Hi trying to set specific date ticks. I don't understand why the following code does not work

figure()
hold on
box on
plot(date1,series1,'k')
plot(date1,series2,'r--')
xlabel('Date')
ylabel('Price')

DateString = {'06/30/2010';'11/30/2010'};
datenum(DateString);
set(gca, 'XTick', datenum(DateString))
dateFormat = 1;
datetick('x', dateFormat)

Answer 1

[Walter Roberson]

datetick('x', dateFormat, 'keepticks')

[EM]

Hi Walter, are you implying that the only adjustment I need is to include 'keepticks' ?

[Walter Roberson]

Yes. datetick() normally ignores any tick positions already set and calculates "nice" tics based upon the time format. So use the 'keepticks' option.

Setting the tick positions after calling datetick() would not work: datetick() sets the tick labels to strings, and those strings would not be reflect the positions you set afterwards.

plotting with datetime objects is even better; datetick was always a bit of a kludge.

[EM]

Thank you!

[EM]

Hi I'm still receiving an error. Can you help?

Here is the code:

figure()
hold on
box on
plot(date1,series1,'k')
plot(date1,series2,'r--')
xlabel('Date')
ylabel('Price')

DateString = {'06/30/2010';'11/30/2010'};
datenum(DateString);
set(gca, 'XTick', datenum(DateString))
dateFormat = 1;
datetick('x', dateFormat,'keepticks')

Here is the error:

Error using matlab.graphics.axis.decorator.DatetimeRuler/validateTicks Value must be a vector of increasing datetime values.

Error in matlab.graphics.axis.decorator.DatetimeRuler/setTicksDelegate

[Walter Roberson]

Your date1 appears to be datetime objects, and you appear to be using R2016b or later. In that case you do not use datetick.

figure()
hold on
box on
plot(date1, series1, 'k')
plot(date1, series2, 'r--')
xlabel('Date')
ylabel('Price')

DateString = {'06/30/2010';'11/30/2010'};
ticlocs = datetime(DateString); %R2014b or later
ticlocs.Format = 'dd-MMM-yyyy';
set(gca, 'XTick', ticklocs);    %R2016b or later

Answer 2

[Peter Perkins]

If you have access to R2016b or later, you will probably be much happier using datetime rather than datenum/datestr, including for plotting:

d = datetime(2015,1,1:500);
x1 = randn(size(d));
plot(d,x1)
ax = gca;
ax.XAxis.TickValues = datetime(2015,1,1)+calquarters(0:6);
ax.XAxis.TickLabelFormat = 'QQQ-yyyy';

[EM]

Can you use this approach to place ticks at specific dates? For example I have 8 specific dates that I'd like to place a tick at. So I cannot simply use a start date and increase it by quarters.

[Walter Roberson]

Yup. For example,

ax.XAxis.TickValues = datetime(2015,1,1)+days([18 143 207 258]);
ax.XAxis.TickLabelFormat = 'MMM dd';

or

ax.XAxis.TickValues = datetime(2015,[1;5;11;14], [17;5;30;19]);
ax.XAxis.TickLabelFormat = 'yy/M/d';

[EM]

Thank you Walter, that is very helpful.

Answer 3

[Med Aymane Ahajjam]

In order for the TickLabelFormat to work, at least in my case, I had to specify:

ax.XTickLabelMode = 'manual';

ax.XAxis.TickLabelFormat = 'HH:mm:ss';