Filling up zeros forward/backward columnwise
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Hi I need to fill up zeros by the previous data columnwise in a matrix containing 5 minutes data for 10 days. each day I have 288 data so total number of rows is 288*10=2880 and number of column if say, 5. if the first data of a given day is zero it will filled up with the next data. Can anybody help by proving MATLAB codes for doing this?
2 Kommentare
Walter Roberson
am 20 Jan. 2014
Is it possible for there to be two 0 in a row? Is it possible for a row to be all 0 ?
Antworten (2)
Image Analyst
am 20 Jan. 2014
Bearbeitet: Image Analyst
am 20 Jan. 2014
Something like this maybe (untested)
[rows, columns] = size(m);
for row = 1 : rows
for col = 2 : columns
if m(row, col) == 0
m(row, col) = m(row, col-1);
end
end
end
3 Kommentare
Image Analyst
am 20 Jan. 2014
You said columnwise so I thought you wanted to go across columns first, in a given row, and then move down to the next row once all the columns in the active row have been processed. I think column-wise means columns first, then rows. I guess you and I have different definitions of column-wise. So you want to go down rows first, and then move over to the next column once all the rows in that column have been processed. Try this (again, untested):
[rows, columns] = size(m);
for col = 1 : columns
% Fill up zeros if column starts with zero.
if m(1, col) == 0
% First row of this column is zero.
firstNonZeroRow = find(m(:, col)~= 0, 1, 'first');
% Make all prior rows have that value.
valueToUse = m(firstNonZeroRow, col); % Get the value.
m(1:firstNonZeroRow-1, col) = valueToUse;
end
for row = 2 : rows
if m(row, col) == 0
m(row, col) = m(row, col-1);
end
end
end
Jos (10584)
am 20 Jan. 2014
This looks like a job for FILLZERO :
3 Kommentare
Jos (10584)
am 23 Jan. 2014
Not working is too vague … What is the problem? Note that you need to perform these steps for a File Exchange file to work on your system:
- Download the file from the File Exchange (and unzip it)
- Copy the m-file to a specific folder (e.g. "Useful_mfiles") somewhere in your user or programming folder (not in a systems or matlab folder).
- Add this folder to the matlab path
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