datenum - Convert to serial date number
The datenum function converts date vectors (defined by datevec) into serial date numbers. Date numbers are serial days elapsed from some reference date. By default, the serial day 1 corresponds to 1-Jan-0000.
N = datenum() returns the serial date numbers corresponding to current date.
N = datenum(Y, M, D) returns the serial date numbers for corresponding elements of the Y, M, and D (year, month, day) arrays.
N = datenum(Y, M, D, H, MI, S) returns the serial date numbers for corresponding elements of the Y, M, D, H, MI, and S (year, month, day, hour, minute, and second) array values.
datenum() datenum(1973,8,4)