csv file reading limits question

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Namaka
Namaka 2011-1-26
Hello, I'm trying to import the data from multiple csv files. My csv files have different numbers of heading lines. for example:
File one:
DATE = 20020414
TIME = 0723
Data 1, Data 2,
1,2
3,4...
File two:
DATE = 20020414
Data 1, Data 2,
1,2
3,4
4,5...
I have a code that works for a single csv file, using csvread/dlmread where I manually assign the row and column limits, but I would like to write a general code that can search for the number of headers in a specific file and adapt limits for file reading accordingly. Is there an easy way to do this? Should I be using a different function to read my data? (textscan, etc?)
  2 个评论
Jan
Jan 2011-1-26
How do you distinct header lines from data lines? Do header lines never start with a number character, but data lines always do?
Namaka
Namaka 2011-1-26
yes, that is the main difference.

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回答（2 个）

Walter Roberson
Walter Roberson 2011-1-26
Provided that you have the same number of columns in each of the files:
fid = fopen(CurrentFileName,'rt');
failed = 0;
if fid < 0
disp(sprintf('Failed to open file: %s', CurrentFileName))
failed = 2;
else
while true
pos_at_line = fseek(fid);
this_line = fgetl(fid);
if ~ischar(this_line)
disp(sprintf('File has no dataset: %s', CurrentFileName))
failed = 1;
break
elseif any(this_line == '=')
continue
else
fseek(fid,pos_at_line,'bof');
break
end
end
if failed == 0
inputdata = textscan(fid, ...... ); %use an appropriate format
end
if failed <= 1
fclose(fid);
end
Namaka
Namaka 2011-1-26
A solution! Since the last header in all my files contains the word "FLAG" I found this line by using the code:
for i = 1:(numfiles)
str=['!grep -n ''FLAG'' ',filefolder,'/',d(i).name,' > hold'];
eval(str);
str=d(i).name;
fid=fopen('hold');
y=fscanf(fid,'%g',[1 1]); %finds the line number at FLAG using g
fclose(fid);
c=csvread(d(i).name,y+1,0,[y+1 0 x-2 8]);
% x is the location of the end of the file I found using a similar method
end

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