in reply to
Date and time difference
It is usually also a very good idea to write your code so that it actually checks the data, to be certain that the specified date/time actually exists. I have probably encountered “GIGO” (and “pseky, esaily-overlookd litle tpyos”) more often in the context of date-strings than anything else.
To that end, using the DATE modules previously mentioned is likely to be a smart thing to do, because these modules are coded defensively. Use a regular expression to pick-apart the date string, then actually check that (say...) the rightmost of these terms was actually extracted, then stuff the list of scalars into the DATE module of your choice.