Hi,
I have the following type of data:
myData <- data.frame(x = 1:5, y = letters[1:5], xDate =
seq(as.Date("2001/2/1"), as.Date("2005/2/1"), by="year") )
> myData
x y xDate
1 a 2001-02-01
2 b 2002-02-01
3 c 2003-02-01
4 d 2004-02-01
5 e 2005-02-01
What I need is a new column, say xDate2, that for each xDate (or for each
unique combination of x,y, and xDate), I will have few days before and few
days after, as follow:
myData
x y xDate xDate2
1 a 2001-02-01 2001-01-30
1 a 2001-02-01 2001-01-31
*1 a 2001-02-01 2001-02-01* (original row)
1 a 2001-02-01 2001-02-02
1 a 2001-02-01 2001-02-03
2 b 2002-02-01 2002-01-30
2 b 2002-02-01 2002-01-31
*2 b 2002-02-01 2002-02-01* (original row)
2 b 2002-02-01 2002-02-02
2 b 2002-02-01 2002-02-03
...
5 e 2005-02-01 2005-01-30
5 e 2005-02-01 2005-01-31
*5 e 2005-02-01 2005-02-01 *(original row)
5 e 2005-02-01 2005-02-02
5 e 2005-02-01 2005-02-03
The actual xDate on my data is not as nicely sequenced as the above example.
But the idea is the same, that I would like to get few days before and after
for my each xDate.
I've tried tapply, by and direct assignment like myData$xDate2 <- seq(xDate
- 5, xDate + 5, by="day") and the like, but without result.
Any idea is appreciated.
Thanks much,
Ferry
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