TF = lt (A, B) is the equivalent of the syntax TF = A < B and returns a logical array set to true where the corresponding element of A is an earlier point in time than that of B, and false otherwise.

Both operands must be datetime arrays and either both have a time zone or both be unzoned; zoned arrays are compared by their absolute instants, so the two time zones may differ. A and B must be size compatible. Not-A-Time compares as false against anything, just like NaN.

Source Code: datetime