How can I change data directly from the plot ?

How can I divide the data on the first plot by 2 using command line ?

I mean is there a way like

ax = gca ; 
ax.Children(2).Children(1).Ydata/2 ; 

Answer 1

[Mehmed Saad]

There are two axes in your figure (two subplots) and each axes contains three line

access the gcf

f = gcf;

Now to see how many childrens it has type on cmd

f.Children

ans =

4×1 graphics array:

Legend (2.5e-07-1e-06-5e-09 0.25, 5e-07-1e-06-5e-09 0.5, 1e-06-1e-06-5e-09 1)

Axes

Legend (1e-06-5e-07-5e-09 2, 5e-07-5e-07-5e-09 1, 2.5e-07-5e-07-5e-09 0.5)

Axes

So two axes and two legends

To access first axes

f.Children(2) % for 2nd axes use f.Children(4)

ans =

Axes with properties:

XLim: [5 40]

YLim: [0 1.6000e-06]

XScale: 'linear'

YScale: 'linear'

GridLineStyle: '-'

Position: [0.1300 0.1100 0.7750 0.3768]

Units: 'normalized'

Show all properties

to see its childrens

f.Children(2).Children

ans =

3×1 Line array:

Line (1e-06-1e-06-5e-09 1 )

Line (5e-07-1e-06-5e-09 0.5)

Line (2.5e-07-1e-06-5e-09 0.25)

Access first line Ydata

f.Children(2).Children(1).YData

ans =

1.0e-06 *

0.6266 0.3493 0.1950 0.1380 0.1078

To change it i.e. divide it by 2

f.Children(2).Children(1).YData = f.Children(2).Children(1).YData/2;

Similarly you can do that for other lines

[andrea]

Yes, is what I've done but the plot seems not refresh the data, is it possibel ?

Answer 2

[Constantino Carlos Reyes-Aldasoro]

To complement what Mehmed has just posted. It would be even easier if when you first create your figure, you save in handles all that is necessary, for instance:

x =[1 2 3 4];y=[4 3 2 3];
z = rand(8);

hFigure     = figure(1);
hAxis1      = subplot(2,1,1);
hLines      = plot(x,y);
hAxis2      = subplot(2,1,2);
hImage      = imagesc(z);

Then you can modify your figure by modifying the data of the handles, say you want to change the image from z to z2 then you change it like this

z2          = randn(8);
hImage.CData=z2;

or like this

hAxis2.Children.CData  = z2;

Hope that helps.