Datenum Problem

Hi everyone!

I am loading a .txt file into matlab in the following way:

fid = fopen('data.txt');
data = textscan(fid,'%s %s %*f %*s %*f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %*[^\n]','HeaderLines',2,'Delimiter','\b\t','EndofLine','\r');
%disp(data{1});
fclose(fid); 

%GET DATE AND TIME
dateandtime=data{1}(:);

%CONVERT DATETIME TO NUMERIC VALUE

datetimenumber=datenum([dateandtime{:}],'dd.mm.yy HH:MM:SS');

But when I load it like this, matlab brings the data set as cell arrays like this: EDU>> whos data Name Size Bytes Class Attributes

data      1x42            15544862  cell

So when I try to create a numeric value for the date and time (which has a format 'dd.mm.yy HH:MM:SS') matlab creates this variable:

EDU>> whos datetimenumber Name Size Bytes Class Attributes

datetimenumber      1x1                 8  double              

 but this is wrong because my dateandtime cell array has a 31591x1 size, so the datenum should also create a 31591x1 numeric dates and times.

EDU>> whos dateandtime Name Size Bytes Class Attributes

dateandtime      31591x1             3032702  cell

I would really appreciate any hints of how can I fix this and create numeric dates and times for my dateandtime cell.

Have a nice week!

Lourdes

[bym]

can you provide a few lines of data.txt?

[Lu]

Hi proecsm,

Thank you for the reply! My data set looks a bit like this:

Hourtime Name Price1 Price2 Price3 and so on...

19.10.09 09:00:16 BASF 30 31 34

19.10.09 09:00:17 BASF 30 31 34

19.10.09 09:00:18 BASF 30 31 34

19.10.09 09:00:19 BASF 30 31 34

Is there anyway I could transform the Hourtime into numeric value? because apparently Hourtime is not loading as a string since it appears without the usual '' like '19.10.09 09:00:19'. Is there anyway i can do that because datetimenumber=datenum([dateandtime{:}],'dd.mm.yy HH:MM:SS');

is not working :(

Thank you! :)

Answer 1

[Oleg Komarov]

Your textscan is not consistent with the lines you posted:

textscan(fid,'%s %s %*f %*s %*f

For:

         s        s    s  f  f   f
  19.10.09 09:00:16 BASF 30 31 etc...

Should be

data = textscan(fid, ['%s%s%s%*f' repmat('%f',1,n)],HeaderLines,2,'CollectOutput',1);

where n is the number of prices except the first one which is skipped.

No need to specify delimiter and line end (see default behaviour)

EDIT

Even better would be:

fmt = ['%17c%s%*f' repmat('%f',1,40) '%*[^\n]'];
opt = {'HeaderLines',2,'CollectOutput',1};
data = textscan(fid,fmt,opt{:});

dates = datenum(data{1},'dd.mm.yy HH:MM:SS')

[Lu]

Dear Oleg,

Thank you for the reply! It is true, it was not consistent because I wrote the sample data set the way I get it from matlab after doing textscan, but i was already ignoring some columns.

I have one main problem: since i want to create my time intervals, i wanted to convert the datetime column (this is the format of how it looks in my file 'dd.mm.yy HH:MM:SS') into a numeric value, but whenever I type

dateandnumber=datenum([dateandtime{:}],'dd.mm.yy HH:MM:SS');

i get just one output : 734065.375185185

and the problem is I need all the numeric values for all my dateandtime values.

Is there anything I can do to fix it?

Thank you so much! :)

Lourdes

[Lu]

Dear Oleg,

Thank you so much!! This is really helpful and it works!!

Have a nice week!

Lourdes :)

Answer 2

[Andrei Bobrov]

so?

fid = fopen('data.txt');
t = textscan(fid,'%s','Delimiter','BASF');
fid =fclose(fid);
t = t{:};
t = reshape(strtrim(t(cellfun(@(x)~isempty(x),t)))',2,[])';
out = [datenum(t(:,1),'dd.mm.yy HH:MM:SS') str2num(char(t(:,2)))]

[Lu]

Dear Andrei,

Thank you for the help! I don´t entirely get your code but I guess it is trying to eliminate empty spaces? but I don´t have empty spaces in my data set. Could you please explain me a bit more the last two lines of code please? I would really appreciate it :)

Thank you,

Lourdes