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what am i doing wrong here? Invalid expresssion!

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muhammad choudhry
muhammad choudhry on 19 Nov 2020
Commented: muhammad choudhry on 19 Nov 2020
Hi,
I am trying to loop over the code below.
co_ordinates = 102 x 1 double
Indices = 17 x 1 double
code to extract the single value is
XY = co_ordinates (indices(1)+1:indices(2)-1,1)
how can I perform the loop over above line ?
So far I tried!
for i =1:length(co_ordinates)
XY(i) = coordinates(i) (indices(1)(i)+1:indices(2)(i)-1,1(i))
end
but I am getting an error: Invalid expression in the line
  1 Comment
David Hill
David Hill on 19 Nov 2020
Show us an example of what you want XY to be from your other two arrays.

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Answers (1)

Image Analyst
Image Analyst on 19 Nov 2020
Edited: Image Analyst on 19 Nov 2020
You have extra things in () after the variable names. Get rid of those. And you mispelled co_ordinates inside the loop. Try this:
for k = 1 : length(co_ordinates)
XY(k) = co_ordinates(indices(k)+1 : indices(k)-1, k)
end
but indices(k)+1 : indices(k)-1 will be null unless the indices are negative values since you're going from a high value to a low value. Maybe you wanted
for k = 1 : length(co_ordinates)
XY(k) = co_ordinates(indices(k)-1 : indices(k)+1, k)
end
But that would give a range of values for the first index, and you can't stuff a vector into the single element of XY. It's hard to know you really want/need without you actually describing more what "Extract the single value" means to you.
  2 Comments
muhammad choudhry
muhammad choudhry on 19 Nov 2020
Please find the attach! I have modify the code but I am still getting error it is because i used i+1 in the code and at the final value it is still adding 1....... I am not sure how to get this right....
What code is doing:
reading the image extracting contours C values, base on the vertices in it I am extracting the contours arrays hence would like to do in a way it will save the arrays of all contours separtely. I have attached the frame and code here

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