Thread Subject: Remove the last line from a .csv file.

Hi guys,

Basically what I want to do is write an array I have to a .csv file and then add a string to the top of the array. I have done this successfully using the following code.

csvwrite('data.csv',data);

dlmwrite('data.csv',['header string' 13 10 fileread('data.csv')],'delimiter','');

However I've noticed that each of these lines adds a blank line to the end of the file. When I open the .csv file in my other analysis software I get an error and this is only solved by removing one of the blank lines from the end.

Any reccomendations would be greatly appreciated!

Thanks,

Mark

Mark Hard wrote:

> Hi guys,
>
> Basically what I want to do is write an array I have to a .csv file and
> then add a string to the top of the array. I have done this successfully
> using the following code.
>
> csvwrite('data.csv',data);
>
> dlmwrite('data.csv',['header string' 13 10
> fileread('data.csv')],'delimiter','');
>
> However I've noticed that each of these lines adds a blank line to the
> end of the file. When I open the .csv file in my other analysis software
> I get an error and this is only solved by removing one of the blank
> lines from the end.
>
> Any reccomendations would be greatly appreciated!


Why in the world are you writing the data first, then turning around and
overwriting it after reading it???????

Write the header, then then the data and be done.

I'd think that would solve the problem...

--

On Jun 16, 1:34 am, "Mark Hard" <GerryTheLe...@hotmail.com> wrote:
> Hi guys,
>
> Basically what I want to do is write an array I have to a .csv file and then add a string to the top of the array. I have done this successfully using the following code.
>
> csvwrite('data.csv',data);
>
> dlmwrite('data.csv',['header string' 13 10 fileread('data.csv')],'delimiter','');
>
> However I've noticed that each of these lines adds a blank line to the end of the file. When I open the .csv file in my other analysis software I get an error and this is only solved by removing one of the blank lines from the end.
>
> Any reccomendations would be greatly appreciated!
>
> Thanks,
>
> Mark

Oh what a muddle you've gotten yourself into using these functions.

If you use fprintf instead, it's much simpler:
[nrows,ncols]=size(data);
fid=fopen('data.csv','wt');
fprintf(fid,'%s\n',Header); % Assumes Header is a string
fmt=repmat('%0.3f,',1,ncols); % Set up format
fmt=[fmt(1:end-1) '\n']; % Remove comma and put LF at the end
fprintf(fid,fmt,data'); % Need to transpose mx
fclose(fid);

Thanks very much guys. I've seen the error of my ways!

On Jun 16, 12:34 pm, "Mark Hard" <GerryTheLe...@hotmail.com> wrote:
> Thanks very much guys. I've seen the error of my ways!

Just to be clear: A file is not *Random* Access Memory (RAM),
but *Sequential* Access Memory. With variables in RAM you can
access this or that part at will; with data in a file you need
to access them in the order they appear in the file.

Which means that you need to write the data to your file in
the order they are supposed to appear in the file. So if you
want a header and then data, then you need to write the header
first, before you write the data.

Rune