timedelta in QSTK

Question

I am going through QSTK and in tutorials they use datetime.timedelta I am curios what is the purpose of such command in stock related environment. I found some articles on what timedelta is but clearly I am not grasping it since I am clueless what this means:

timeofday= datetime.timedelta(hours=16)
timestamps = du.getNYSEdays(startday,endday,timeofday)

What is a purpose of timedelta as an argument for QSTK or in general.

What is your question? It's not particularly clear, which makes answering it difficult. — Sam Mussmann, Nov 26 '12 at 22:29
what is timedelta in this context, as in why is it necessary to pass as argument — rodling, Nov 26 '12 at 22:33
Can you edit your question to make that more clear? Thanks! :-) — Sam Mussmann, Nov 26 '12 at 22:37

score 3 · Accepted Answer · answered Nov 26 '12 at 22:34

A timedelta is just an amount of time. In this case, "16 hours".

They're useful because they can be used to manipulate dates and times. Say you've got a datetime object that represents "May 21, 2002 at 6am". If you add your timedelta to that datetime, you'll get "May 21, 2002 at 10pm".

You can also use them to compare datetime objects. If todays_lunch is defined as "11/26/2012 at 12pm" and today's dinner is "11/26/2012 at 6pm", then you can do:

>>>todays_dinner - todays_lunch < timeofday
True

Without more of the code (or maybe just a better understanding of the NYSE than I have), it's hard to tell what this particular case is doing. But it's something to do with manipulating datetime objects in 16-hour intervals.

1600 is when markets close, this kind of clears it up thanks. They are asking for closing price — rodling, Nov 26 '12 at 22:37

timedelta in QSTK

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