MATLAB: Separate one column in an imported matrix

importing excel dataload

Hello,

Basically, I have a table where the last column really has several values. The number of these values differ. What I would like is to import the data so that it is all in a matrix and instead of one column showing points, you have a subsequent series of columns from (point one) to (point n). It is fine to fill zeros so that every row has the same number of vectors. I attached a portion of my data sheet. MatLab tries to sum or multiply these values when importing; I took a first pass at trying to use textscan and splitcells and other things I saw on the forum but I cannot get it to run correctly. Anyone know the easiest way to do this? I said C=textscan(segments1,'%f') and got that the first input must be a valid file-id or non-empty character vector.

Best Answer

The way I'd do it:

t = readtable('test11_1.txt');  %import as table
t.PointIDs = rowfun(@(s) sscanf(s, '%f,', [1 Inf]), t, 'InputVariables', 'PointIDs', 'ExtractCellContent', true, 'OutputFormat', 'cell')

It's probably better to keep the data in a table rather than storing it in a matrix, particularly one padded with 0s.

Related Solutions

MATLAB: Readtable from i-th row to last row

Try this

opts = detectImportOptions(filename,'NumHeaderLines',6)

T = readtable(filename,opts)

MATLAB: Importing Column Vectors Sequentially

"... in ... import app those are the cells ... tab delimited..."

In that case, use textscan and a format string set up to read the desired columns. This isn't particularly difficult to automate depending on the columns wanted...

cols={'D','F'};           % the list of wanted columns
fmt=[];                   % empty string to build format string into
for i=1:length(cols)      % over the number of columns to read
  fmt=[fmt repmat('%*f',1,cols{i}-'A') '%f'];  % skip N-1, read 1
end
fmt=[fmt '%*[^\n'];       % and then skip rest of line
fid=fopen('filename','r');
data=cell2mat(textscan(fid,fmt,'delimiter','\t', ...
                                'headerlines', 18, ...
                                'collectoutput',1));  % and read the file
fid=fopen(fid);

There's a section Large Text Files linked to at the doc for textscan that describes how to read a file in blocks if this still errors out on memory altho if the import tool can do it, the above likely will work as I'd venture it's what it does as a first try, anyway...

Best Answer

Related Solutions

MATLAB: Readtable from i-th row to last row

MATLAB: Importing Column Vectors Sequentially

Related Question