MATLAB: Datenum failed

Question

I am using the datenum function to convert a time stamp in my dataset to a serial number. This is the line that does it:

wind.t = datenum(wind.TheTime,'mm/dd/yyyy HH:MM:SS');

It is failing on one dataset and not on another and I don't understand why. There is nothing different between the two datasets, other than one is much longer.

Both timestamps are formatted the same way, but the longer one gives this error:

Error using ==> datenum at 174 DATENUM failed.

Caused by: Error using ==> dtstr2dtnummx Failed on converting date string to date number.

The info about the timestamp column was found using the 'summary' function below. They are identical.

wind = summary(wind)

TheTime: [27878×1 cell string, Units = TheTime]

summary(wind)

TheTime: [2047×1 cell string, Units = TheTime]

Any help or suggestions would be much appreciated.

Answer 1

Assuming you haven't looked at every string individually, I'd guess the mostly likely cause is a malformed string somewhere in the cell array. You could perhaps use regexp to check that the strings all do, in fact, match the assumed pattern.

Something like this should work:

nnz(cellfun(@isempty,regexp(wind.TheTime,'\d+/\d+/\d\d\d\d\s+\d+:\d+:\d+')))