Iterating through a structure

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Jordan Coombs
Jordan Coombs on 12 Dec 2020
Commented: Jordan Coombs on 13 Dec 2020
I am trying to create a mask using by 168x1 struct but whenever i run the code i get this error - Expected one output from a curly brace or dot indexing expression, but there were 168 results.
Is there a way i can iterate through the structure and create a mask out of these fields.
Any help is appreciated
[x,y] = pixcenters(R);
[X,Y] = meshgrid(x,y);
names = fieldnames(S);
no_afr_stru = cell2struct(filt_nonaf_country,names,1);
fn = fieldnames(no_afr_stru);
rx = no_afr_stru.X(1:end-1);
ry = no_afr_stru.Y(1:end-1);
mask = inpolygon(X,Y,rx,ry);
  2 Comments
Ive J
Ive J on 13 Dec 2020
Please provide more details so that everyone can reproduce your error. For starters, what are X, Y, rx and ry? can you provide an example?
Jordan Coombs
Jordan Coombs on 13 Dec 2020
X & Y are the points from my geotiff file and rx and ry are the points from the countries which i want to mask on my tiff file. as my struct no_afr_stru is 168x1 i want to iterate over all 168 lines in the structure and apply them all to the mask. Hope this helps!

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Accepted Answer

Rik
Rik on 13 Dec 2020
You can index a struct in a loop:
rx = no_afr_stru(n).X(1:end-1);
ry = no_afr_stru(n).Y(1:end-1);

More Answers (1)

Ive J
Ive J on 13 Dec 2020
Edited: Ive J on 13 Dec 2020
Try this:
mask = arrayfun(@(x)inpolygon(X, Y, x.X, x.Y), no_afr_stru, 'UniformOutput', false);
  2 Comments
Rik
Rik on 13 Dec 2020
I suspect the goal is to create a single mask, which would be easier with a loop. Also, arrayfun will have an overhead.
Jordan Coombs
Jordan Coombs on 13 Dec 2020
you would be correct there sorry i should have specified

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