filter certain column in an array

I have data array as following, the first 2 lines are not shown in the csv file.

----Student 1---- ----Student 2---- ----Student 3---- ----Student 4---- ----Student 5---- %not shown in csv%
Eng. Math Science Eng. Math Science Eng. Math Science Eng. Math Science Eng. Math Science %not shown in csv%
50   20   100     80   80   60      80   50   60      90   100  20      50   100  100
80   30   60      50   60   70      80   30   70      50   0    90      70   100  90
60   70   80      30   90   40      100  90   60      10   80   40      80   40   60

I have created a table to allow the user to filter some students out of this table. For example, if student 4 is selected. StudentKept = [1 2 3 5]. Then may I know how to re-construct the csv file with only StudentKept??

Current coding:

StudentKept=find([data{:,2}]==0);
for m = studentKept
   dataArrayFiltered=[dataArrayAll(studentKept,1)];
end

[Sivakumaran Chandrasekaran]

have you checked the option csvwrite.

[Adithya Addanki]

Hi,

There is no direct way of doing this through "csvwrite" or "xlswrite". I think you will be able to achieve it in a programmatic way.

You may need to extract the columns that are not being selected(may be a flag to see if it is selected or not? or indexing actually through all the data and selecting the unfiltered data based on row and column indexes).

Thank you,

Adithya

Answer 1

[Guillaume]

The first thing to do is to get rid of the flat format of your file, which is not helpful for manipulating data. Reshaping the data so that students are the third dimension makes it easy to filter by student:

studentkept = [1 2 3 5];
studentdata = csvread('somefile.txt');
studentdata = reshape(studentdata, size(studentdata, 1), 3, []); %pages no correspond to student
keptdata = studentdata(:, :, studentkept); %now, it's easy to filter

You can save it back to the original format by reshaping back to the flat format:

csvwrite('someotherfile.txt', reshape(keptdata, size(keptdata, 1), []));