how to read spread sheet row by row iteratively ?

Hello everyone,

I have an excel sheet that contains several rows with different lengths. I want to read these rows, using the command xlsread, iteratively ( in each iteration the code read one row) that is to avoid reading all the spreadsheet once which will generate matrix with NaN elements that will affect my calculation. I will set variable to hold the row and clear this variable after each calculation.

Thanks

Answer 1

[Walter Roberson]

Yes, it is possible to specify a Range that is a single row. You would want to use xlsread1 from the File Exchange to improve the speed -- though I understand that in R2015b they do something similar natively.

But there is another way:

num = xlsread('TheFileName.xls');
num_by_line = mat2cell(num, ones(1,size(num,1)), size(num,2));
trimmed_lines = cellfun(@(C) C(~fliplr(cumprod(fliplr(isnan(C))))), num_by_line, 'Uniform', 0);

Now trimmed_lines is a cell array of numeric vectors, one entry per row, in which all the trailing NaN have been removed.

A question would be whether you want the same thing to happen to leading NaN.

Note: NaN also occur in the numeric form in places where strings occur. If you have strings that you want to preserve then the code gets more complex. Leading NaN can occur as row headers.