Let's generate two sample datetime objects and set their Format to show just the times with fractional seconds.
N = datetime('now');
N.Format = 'hh:mm:ss.SSS'
X = N + seconds(10*randn);
X.Format = 'hh:mm:ss.SSS'
What's the difference between the two? Is it less than 5 seconds?
d = abs(X-N);
d.Format = 'mm:ss.SSS'
d < seconds(5)
Or you can convert the difference into a number of seconds and compare with the number 5.
sec = seconds(d)
sec < 5
If you want to round the datetime object you could use dateshift to shift to the 'start' or 'end' of the second or shift to the 'nearest' second.
dateshift(N, 'start', 'second')
dateshift(N, 'start', 'second', 'nearest')
dateshift(N, 'end', 'second')
