Dates and arrays
There is a one line nextfri function defined in the zoo-quickref vignette and replacing 5 with 1 in its definition will give you next Monday. The prior Monday is 7 days before that so take the closest of the two. See R News 4/1 for more about dates.
On Wed, May 13, 2009 at 4:23 PM, myshare <mraptor at gmail.com> wrote:
hi, I have a and data frame with date-column and some other columns. My first question is what is the fastest way to get the index of an array if I know the value f.e
x = c(4,5,6,7,8)
so i know the value is 6.. i.e. the index is 3. What I currently do is loop over the array, I was thinking if there is faster more direct way. The next one...is I have a data frame one of the columns is Date based (stored as string), as you may be guessed I have the date and I want to find the index ;), but here is one more complication. The dates are not sequential, but only dates when the day is Mon-Fri i.e. for Sat and Sun i don't store information. So I have first convert the date I have into the closest Monday. Let me give you one example. Let say I have the date 2000/01/01 (Sat), now to be able to find any information I have to find the nearest Monday in this case it is 2000/01/03 (Mon).. So now that I have this new date I can find the index of the element in the array where it is stored and from this I can get the real data I need. In short conversation is from Data ==> nearest Monday ==> index of the element in the array where it is stored. thank you very much
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