Plot Time series data in date format

4 vues (au cours des 30 derniers jours)
dedenlaut
dedenlaut le 9 Déc 2011
Hello,
I confused... if i have input data in .txt
exp : abc.txt
20110313000000 3.87
20110313000015 3.871
20110313000030 3.87
20110313000045 3.869 . . 20110313000130 3.844
20110313000145 3.83
20110313000200 3.824 ..
first column is date format (yyyymmddHHMMSS) and second column is the data
how if I want to plot in X axes in format '2011-March-11 00:15' (yyyy-MM-dd HH:MM)?
I write matlab
load abc.txt;
plot(abc(:,1),abc(:,2));
title('Tide time series 1116');
xlabel('time');
ylabel('Sea water level');
but it didn't give the right plot, anyone can help this basic problem.. thank you

Réponse acceptée

Walter Roberson
Walter Roberson le 9 Déc 2011
You can break up the number in the first column using pure numeric ways similar to what I used in http://www.mathworks.com/matlabcentral/answers/21688-is-there-a-more-effitiant-way-than-datenum-num2str-ftstempin-1-1
And if you don't have a lot of data to input and just want to get the code done, you can instead use
x = datenum(cellstr(num2str(abc(:,1))), 'yyyymmddHHMMSS');
plot(x, abc(:,2))
datetick('x', 'yyyy-mmmm-dd HH:MM');
Note the small modification of your format, from MM to mmmm as MM is minutes but you want the month name which is coded mmmmm
  1 commentaire
dedenlaut
dedenlaut le 10 Déc 2011
Thank you Walter...
but I put this code
{load abc.txt;
x=datenum(cellstr(num2str(abc(:,1))),'yyyymmddHHMMSS');
plot(x,abc(:,2))
datetick('x', 'yyyy-mmmm-dd HH:MM');
title('Tide time series 1116');
xlabel('time');
ylabel('Height');}
but show the error
??? Error using ==> datenum at 182
DATENUM failed.
Caused by:
Error using ==> dtstr2dtnummx
Failed on converting date string to date number.

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