Importdata fails to import large files

Question

Luca Amerio 2013-10-7

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/89374-importdata-fails-to-import-large-files

评论： Luca Amerio 2013-10-7

采纳的回答： Walter Roberson

在 MATLAB Online 中打开

Hi everybody.

I've have a bunch of large files as the following one:

#  x  1  2  3  4 ...
#  y  5  6  7  8 ...
#  z  10 11 12 13 ...
# Time
   1  87 85 82 81 ...
   2  67 86 19 34 ...
  ... ... ... ... ...

Since i don't know either the number of rows or the number of columns, usually I import them using

data=importdata(filePath,' ',4);

but for some of them (the biggest ones 1.32 and 1.7 GB) this command doesn't work and data is an empty variable.

I managed to solve this with an ad hoc solution deleting the first 4 rows and using the command

data=importdata(filePath,' ');

Since I have a large number of them I would like to have a solution that works for all of them. What can i do?

Thank you

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Walter Roberson 2013-10-7

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/89374-importdata-fails-to-import-large-files#answer_98823

在 MATLAB Online 中打开

fid = fopen('YourFile.txt');
for K = 1 : 4 %skip 4 lines
  fgetl(fid);
end
here = ftell(fid);       %remember where we are
fields = regexp( fgetl(), '\s+', 'split');  %read line, split it into columns
numcols = length(fields);                   %count them
fseek(fid, here, 'bof');;                   %reposition to prior line
fmt = repmat('%f', 1, numcols);             %maybe %d if entries are integral
datacell = textscan( fid, fmt, 'CollectOutput', 1);  %read file
fclose(fid);   %we are done with it
data = datacell{1};