changing the axis of a plot in a way that the data series starts at x=0 at a point at one point on the y-axis and ends on the right end of the plot

hi,

I have this code:

dates=datenum(VIXdate)

y=VIX

plot(dates,y)

%datevc divides the date in different columns, first colum is the year,
%second the month and thrid the day
d=datevec(dates)

%Takes just the year (first column)
d=d(:,1)

%takes every year just once
[a,idx]=unique(d(:,1),'first')

ylabel('VIX');

set(gca,'xtick',dates(idx),'xticklabel',a)

set(gca,'Box','off')

this works fine, but the problem I faces is that the time series (y=VIX) does not start at the left end of the plot but instead there is a space between the y-axis and the first point of the time series. I know that when there are normal values on the x-axis, I can change it, but I am not able to do it with dates, what do I need to do?

[Babak]

Undefined function or variable 'VIXdate'.

Answer 1

[Jonathan Epperl]

This is still not a working example, the variable VIXdate is obviously unknown to us...

So the dirty way again:

ytix = get(gca,'YTick');
set(gca,'YTick',ytix(2:end));

[Locks]

perfect, thanks

I have another similar problem with this code here:

dates=datenum(dataSet(:,1));

%SPX
SPX=dataSet(:,2);

%VIX
VIX=dataSet(:,3);

plotyy(dates,SPX,dates,VIX);

d=datevec(dates);
d=d(:,1);

[a,idx]=unique(d(:,1),'first');

ylabel('S&P 500 Index')
%axis([ 0 2000]);
set(gca,'xtick',dates(idx),'xticklabel',a)
set(gca,'Box','off')

here it shows me on the xaxis both the date as well as the date in numerical form, how can I change that?

Also I would like to change the color from both y axis into black, is that possible?

[Jonathan Epperl]

You should make that a new question, and finally make it so that we can copy and paste your code into our matlab and run it and see what it is you want to achieve.

[Locks]

ok, I did so, it's fine now, thanks

Answer 2

[Mel]

You could also set just the x axis to be the same as your data:

xlim([0 max(dates)])

Answer 3

[Jonathan Epperl]

axis tight

[Locks]

that is working, but I am only looking for that for the x axis but not for the y axis, is that also possible?

[Jonathan Epperl]

Sure. Without knowing what your actual data looks like (it would still be nice if you could post a working minimal example), you could do that:

ylims = get(gca,'YLim');
axis tight
set(gca,'YLim',ylims);

Dirty, but should work.

[Locks]

    dates=datenum(VIXdate)
    y=VIX
    plot(dates,y)

    d=datevec(dates)

    %Takes just the year (first column)
    d=d(:,1)

    %takes every year just once
    [a,idx]=unique(d(:,1),'first')

    ylabel('VIX');

    set(gca,'xtick',dates(idx),'xticklabel',a)

    ylims = get(gca,'YLim');
    axis tight
    set(gca,'YLim',ylims);

    set(gca,'Box','off')

it's working perfectly now, thanks!

in addition, it would be great if the number 0 on the y axis is not shown in the plot due to the fact that it's so near to the numbers on the x axis, is there a way to do that?