How to save x, y plot data in one variable

I have x and y variable, then I plot it plot(x,y,'.'). I also have two functions (red line and black line). I need to save the x,y plot data into one variable for further processing i.e. show the data bigger or less the function only. Is there anyone can help, I'll very appreciate

[KSSV]

You should look in for logical indexing.

[joynjo]

could you give example or reference?

Answer 1

[Jitender Gangwar]

You can store the plot data as illustrated below

>> x = [1 2 3];

>> y = [4 5 6];

>> plotData = plot(x,y);

>> plotData

plotData =

Line with properties:

              Color: [0 0.4470 0.7410]
          LineStyle: '-'
          LineWidth: 0.5000
             Marker: 'none'
         MarkerSize: 6
    MarkerFaceColor: 'none'
              XData: [1 2 3]
              YData: [4 5 6]
              ZData: [1×0 double]

Show all properties

Now the variable "plotData" has an object with properties of the figure which contains the plot. You can now access the properties by using "." operator.

>> plotData.XData

ans =

     1     2     3

>> plotData.XData(2) = 4;
>> plotData.XData

 ans =

     1     4     3

Hope this answers your concern and helps you.

[Adam]

You will need to make sure you save the data from the plot to somewhere else though before you close the figure, if you want this data to persist beyond the lifetime of the figure, else this object will just become a handle to a deleted object and you will lose your data when you close the graph.

[Jitender Gangwar]

As it is correctly pointed out by @Adam, The data from the handle "plotData" needs to be stored before you destroy(OR close) the figure. This can be achieved as follows:

>> plotData = copy(plotData);

PS: Thank you @Adam for your help.