problem axis "x" in my graph

size(XDates)
ans =
     5     1
     
size(E)

ans =
     5    35
     
for i=1:c    
    col=map(i,:);
    plot(Ax,XDates,E(:,i),'DisplayName','Equity','Color',col);    
    if writeText_right
      text(Ax,gg,E(end,i),strcat(num2str(fix(E(end,i)/1000)),"k","***",num2str(i),"-",nome(i)),'Color',col,'Interpreter','none');
    end
end

In size(XDates) i see 5 element but in the graph there are date pairs

[Star Strider]

The date ticks appear to be separated by 12 hour intervals.

Answer 1

[Image Analyst]

It automatically adds x tick labels and sometimes they are not exactly what your x vector was. If you want to specify exactly what they are use xticks and xticklabels.

Answer 2

[Steven Lord]

Those seem reasonable to me. They're showing the month and date along with the time of data for each of your X coordinates. I suspect you've created them in a format that include this information when the datetime array is displayed.

x = datetime(2023, 10, 30):datetime(2023, 11, 03)

x = 1×5 datetime array
   30-Oct-2023   31-Oct-2023   01-Nov-2023   02-Nov-2023   03-Nov-2023

x.Format = x.Format + " HH:mm"

x = 1×5 datetime array
   30-Oct-2023 00:00   31-Oct-2023 00:00   01-Nov-2023 00:00   02-Nov-2023 00:00   03-Nov-2023 00:00

plot(x, 1:5, 'o-')

If you want to control which ticks are displayed, use the xticks function. If you want to control the formatting of the ticks, use xtickformat. To eliminate the year at the lower-right corner of the axes, if you're using release R2023b or later use the xsecondarylabel function.

figure
plot(x, 1:5, 'o-')
xticks(x([1 3 4 5])) % Skip tick 2
xtickformat('MM/dd@HH:mm')
xsecondarylabel(Visible=false)

If this isn't the problem that you had in mind when you posted your question, please clarify how you'd like the apperance of the figure to be different.

[aldo]

   BackTest_Vect_Fine=app.Eq.Live.FinishingDate;
   BackTest_Vect_Inizio=BackTest_Vect_Fine-gg+1;
   XDates = [datetime(datestr(BackTest_Vect_Inizio:BackTest_Vect_Fine))];
    
   BackTest_Vect_Fine = 

  datetime

   2023-11-03


  BackTest_Vect_Inizio = 

  datetime

   2023-10-30


  XDates = 

  5×1 datetime array

   2023-10-30
   2023-10-31
   2023-11-01
   2023-11-02
   2023-11-03

here there is Xdates....it's build using 
     XDates = [datetime(datestr(BackTest_Vect_Inizio:BackTest_Vect_Fine))];

i think che problem is : XDates = [datetime(datestr(BackTest_Vect_Inizio:BackTest_Vect_Fine))];

but is it possible to have only the date in the dateTime format? (I don't need to use the time)

if i write in main code "datetime.setDefaultFormats('defaultdate','yyyy-MM-dd')" i resolve my problem"?

i want to get as pic below! this is correct..

but how can i create XDates correctly?

[Steven Lord]

i think che problem is : XDates = [datetime(datestr(BackTest_Vect_Inizio:BackTest_Vect_Fine))];

Don't use datestr. You don't need it in this case as the colon operator works just fine for datetime arrays.

T1 = datetime('today')

T1 = datetime
   06-Nov-2023

T2 = T1 + days(7) % next Monday, as I'm running this code on a Monday

T2 = datetime
   13-Nov-2023

V = (T1:T2).'

V = 8×1 datetime array
   06-Nov-2023
   07-Nov-2023
   08-Nov-2023
   09-Nov-2023
   10-Nov-2023
   11-Nov-2023
   12-Nov-2023
   13-Nov-2023

but is it possible to have only the date in the dateTime format? (I don't need to use the time)

Sure. The datetime documentation page has a section on the Format property of datetime arrays. If you don't want to include any of the time components in your array's Format property you don't need to include it. Just build the format you want. For example, let's tweak the default display Format for a datetime array that includes both date and time information.

N = datetime('now')

N = datetime
   06-Nov-2023 20:31:24

N.Format

ans = 'dd-MMM-uuuu HH:mm:ss'

Let's include the name of the day of the week (eeee), the full name of the month (MMMM), the day of the month (dd), the year (yyyy), the day of the year (D), and some text wrapped in single quotes that datetime will use unchanged in the display (not treating the d in 'day' as "Day of the month, using one or two digits", for example.)

F = "eeee, MMMM dd yyyy, 'day' D 'of the year'"

F = "eeee, MMMM dd yyyy, 'day' D 'of the year'"

N.Format = F

N = datetime
   Monday, November 06 2023, day 310 of the year

You may need to call xtickformat with F as input instead of specifying it as the Format of the data you plot.

[aldo]

thank you for explenation

Answer 3

[aldo]

but there is still the problem... Leaving aside the writing of the dates on the x axis, I saw that using 1:5 as an interval gives me 10 steps at 0.5 distance

[r,c]=size(E);

map = hsv(c);

map=map(randperm(c),:); %%AGGIUNTO .. cosi' estrae sequenze a caso ed evito di vedere colori simili vicini

hold(Ax, 'on')

for i=1:c

col=map(i,:);

plot(Ax,1:r,E(:,i),'DisplayName','Equity','Color',col);

if writeText_right

text(Ax,gg,E(end,i),strcat(num2str(fix(E(end,i)/1000)),"k","***",num2str(i),"-",nome(i)),'Color',col,'Interpreter','none');

end

end

>>

r

[Image Analyst]

I see you accepted @Steven Lord's answer so I guess you got it figured out with his help.

[aldo]

I accepted the answer believing that the problem was using xticks(1:n) but that wasn't the case...I removed the acceptance of the answer

[aldo]

but if you want you can help me

[aldo]

i undrestand what is the problem: @Steven Lord

x = datetime(2023, 10, 30):datetime(2023, 11, 03)

x.Format = x.Format + " HH:mm"

plot(x, 1:5, 'o-') (Immagine.png)

but if I enlarge it to full screen I get the x axis intervals doubled (Immagine1.png)