MATLAB: How to make datenum more efficient for large arrays

Question

I am using textscan() to create an matrix that is 3,081,680 rows long. The very first column, A{1}, is the timestamp column, and it's elements look like this:

"2011-01-23 18:38:30"

I have tried using datenum() to convert this, but it is either taking too long or not working at all (longer than ten minutes). Is there a way I can make this more efficient?

Thanks!

Answer 1

What is the purpose ultimately? Do you need an accurate time stamp which accounts for the date and time? If you were computing daily averages for 2011 only, for example, we could find a way to generate month/day IDs probably faster than DATENUM.

Otherwise, there are FEX contributions, e.g. this one by Jan Simon: http://www.mathworks.com/matlabcentral/fileexchange/28093-datestr2num

as well as a few relevant threads, among which: http://undocumentedmatlab.com/blog/datenum-performance/