Extract data from a structure

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jfrazie9
jfrazie9 on 26 Mar 2018
Answered: Ameer Hamza on 21 Apr 2018
I have a "1x1 struct" with 2 fields. One of the fields is data and is a 7909x10 double, while the other field is textdata that is a 1x1 cell containing the header of the output file.
I do not know how to make it so that I only have the data field that is a 7909x10 double. From there I only need columns 1,2,3 and 6 from those 10 columns and would like to delete the other 6 columns to make a new data structure.

Answers (2)

Birdman
Birdman on 26 Mar 2018
One approach:
A.a=A.a(:,[1 2 3 6])
where A is struct and a is its field.
  4 Comments
Birdman
Birdman on 26 Mar 2018
Yes, for instance:
A.a(16:20,1)
will extract the values in column 1 from row 16 to row 20.
jfrazie9
jfrazie9 on 26 Mar 2018
My mistake I was unclear, the first column is the pathID numbered 1-55, where there are approximately 142 rows with pathID = 1, another 142 with pathID = 2. How do I sort based on the value in the first column would be a better question?

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Ameer Hamza
Ameer Hamza on 21 Apr 2018

From your questions and comments, the following solution will work for you. Suppose you original struct is A and you want to create another struct object B by deleting some columns of A and sorting rows according to column 1.

B = A;
B.data = B.data(:, [1 2 3 6]); % delete columns of data
[~, ind] = sort(B.data(:,1)); % get sorted indexes for column 1
B.data = B.data(ind, :); % now sort all rows of data matrix.

This will give you required struct B.

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