dlmwrite/csvwrite cannot open file error

Hi, I'm trying to write a script that saves a new file for each day in data taken over the course of a year. I think I have everything right, but I keep getting an error that says I can't open the file. In my mind, it's not supposed to be opening the file, it's supposed to be writing it, but anyway, any help as to where I went wront would be wonderful. Code is included below, then the error message I got.

function [Filetosave]=splitdate(InputFile)
%This function will take a given file and split the data apart by day for
%to limit file sizes.  It should recognize Dates of string, number or
%vector format, so long as vector format is |Y|M|D|H|M|S|.
Date=InputFile(:,1);
if isnumeric(Date)
    %date is datenum
    check='num';
    if Date<600000
        MatTime = (Date + (693960));
    else
        MatTime=Date;
    end
elseif iscell(Date)
    %date is datevec
    MatTime=datenum(Date);
else
    %date is datestr
    check='string';
    MatTime=datenum(Date);
end
[yr,mo,day,hr,min,sec]=datevec(MatTime);

for n=(1:numel(Date))
    if (n)==1
        Filetosave=InputFile(1,:);
    elseif day(n)==day(n-1)
        Filetosave = vertcat(Filetosave(:,:),InputFile(n,:));
    else
        nameitthis=sprintf('Date_%d/%d/%d.csv',mo(n-1),day(n-1),yr(n-1));
        dlmwrite(sprintf('%s',nameitthis),Filetosave);
        Filetosave=InputFile(n,:);
    end
end
end

Error message looks like this, and if I used csvwrite, it gave the same thing, but with a error in csvwrite calling the dlmwrite function.

Error using dlmwrite (line 124)
Could not open file Date_1/4/2011.csv

Error in splitdate (line 32)
        dlmwrite(sprintf('%s',nameitthis),Filetosave);

Thanks in advance!

Answer 1

[per isakson]

dlmwrite is a function written in m-code. Every time you run dlmwrite it opens and closes the file.

• 'Date_1/4/2011.csv' is not a legal file name. Or the folders 'Date_1' and '4' do not exist.
• dlmwrite(sprintf('%s',nameitthis),Filetosave); is a bit overdoing: dlmwrite(nameitthis,Filetosave);

[Mike Beacham]

I didn't even think about the slashes being folders. Whoops. Changed to Date_1-4-2011 and more or less happy, except it only exports one file. I'll keep working. Thank you!