how to read bytes using fread or in a matrix

Question

kumar panduga 2016-4-30

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回答： Walter Roberson 2016-4-30

I am using fread to open'.dat' files. The file has variables with its values displayed in matrix. Every column in assigned a variable and each column is of different length(1st column 4 bytes, 2nd column 2 bytes etc) I have tried opening 1st column but unable to open 2nd column. I would like to know how to all columns.

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dpb 2016-4-30

Need detailed description of file format. Sounds more like ASCII file from the above rather than stream (unformatted) file. And, files are record-oriented, not by column.

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Answer 1

Walter Roberson 2016-4-30

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https://ww2.mathworks.cn/matlabcentral/answers/281795-how-to-read-bytes-using-fread-or-in-a-matrix#answer_220172

在 MATLAB Online 中打开

collength = [4, 2, ... etc];
fmt = sprintf('%%%ds', collength);
fid = fopen('MyFile.dat', 'r');
datacell = textscan(fid, fmt, 'Delimiter', '', 'Whitespace', '');
fclose(fid);

Now datacell{K} is the K'th column as a cell array of strings.

I did not attempt to convert to numeric because you gave us no information that would suggest the columns are numeric. It might be appropriate to use %%%df or %%%dd