Matlab xlsread在行1048576之后切断文件

1 回答

• 2

  我发现将BIG csv文件读入Matlab的最快方法是对它们进行内存映射并将内容解析为单个字符串 . 尝试使用此示例代码：

  fname = 'file.csv';
  fstats = dir(fname);
  % Map the file as one long character string
  m = memmapfile(fname, 'Format', {'uint8' [ 1 fstats.bytes] 'asUint8'});
  textdata = char(m.Data(1).asUint8);
  
  % Find the end of each line, and use the line ends to form an index array
  row = strfind(textdata, sprintf('\r\n'));
  row = [[1; row(1:end-1)'+2] row' - 1];
  % Fix-up if there is no \r\n at the end of the last line
  if (row(end) < fstats.bytes - 2)
      row = [row; [row(end) + 2, fstats.bytes]];
  end
  numrows = size(row, 1);
  % Create output variables
  Time = zeros(numrows, 1);
  Value = zeros(numrows, 1);
  
  % Parse each line of the data (I'm ignoring the first line for simplicity)
  for RowNum = 2:numrows
      data = textscan(textdata(row(RowNum,1):row(RowNum,2)), '%[^,]%f', 'delimiter', ',');
      Time(RowNum) = datenum(data{:});
      Value(RowNum) = data{2};
  end
  
  % Remove the file mapping
  clear('m');
  

  回复于 2024-04-28T00:49:47+08:00