MATLAB: Readtable from i-th row to last row

data importimporting excel dataMATLABreadtable

Hi,

I am looking for a solution to read an Excel table via readtable from a specific row on down to the last row. I know in which row to start, but I don't know in before which row exactly is the last row.

The only idea I had by now was doing something like

data = readtable(workbookFile, 'sheet', sheetName, 'ReadVariableNames', true, 'FileType', 'spreadsheet', 'UseExcel', false, 'Range', '7:50000');

where 7 ist the row to start the import and 50000 is a valua that high, it would never be reached. The next step would be to delete all the empty rows, that were created (I'm still figuring out how to do it but thats not a part of my question).

That doesn't seem to be very efficient to me. Does anybody have a better solution?

Best Answer

Try this

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

T = readtable(filename,opts)

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MATLAB: Sum every i-th row in matrix seperately

function [Qs] = moyenneQ (yearMin, yearMax)
%Function that calculates the annual average from the data at the daily time step.
Data = load('QsMC_Mars.mat');
QsMC = Data.QsMC;
nYear = yearMax - yearMin + 1; 
Qs = zeros(nYear, size(QsMC, 2));  % Pre-allocate
iStart = 1;
for i = 1:nYear
   year = yearMin + i - 1;
   nbrJour = 365 + leapyear(year);
   iEnd = iStart + nbrJour - 1;
   if iEnd >= size(QsMC, 1)   % Not "length"!
      break
   end
     Qs(i, :) = sum(QsMC(iStart:iEnd,:));
     iStart = iEnd+1;
  end
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MATLAB: Reading Selected Columns from an Excel Using the “readtable” Option

readtable does not accept disjoint ranges (e.g. 'A50:A10000,C50:C10000') so you don't have a choice but read the B column as well and discard afterward:

Table_1 = readtable('FileName.xlsx','Sheet','SheetName','Range','A50:C10000'); %read column A to C
Table_1(:, 2) = [];  %discard B column

Alternatively, you could use detectImportOptions then modify the import options to remove the columns you don't want:

opts = detectImportOptions('FileName.xlsx','Sheet','SheetName','Range','A50:C10000');  %still have to specify the full range
opts.SelectedVariableNames = opts.SelectedVariableNames([1, 3]);  %ignore second column
Table_1 = readtable(FileName.xlsx', opts)

Another workaround might be to name the desired range in excel but I can't remember if you can create named disjoint ranges. If it's possible, you could pass the range name to readtable. Of course, this requires the range to be named beforehand in excel, so may not be practical.

Best Answer

Related Solutions

MATLAB: Sum every i-th row in matrix seperately

MATLAB: Reading Selected Columns from an Excel Using the “readtable” Option

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