[R] select previous date

From: alessandro carletti <alxmilton_at_yahoo.it>
Date: Thu 18 Aug 2005 - 22:49:55 EST


Hi everybody,
could anyone help me in finding a way for selecting from a dataframe each row that comes before another that matches a condition?

EXAMPLE:
df

raw.number  name     date      temp
1            aaa   2001-04-15   15
2            aaa   2001-01-15   12
3            aaa   2001-03-15   13
...
i-1          bbb   2002-04-15   15 
i            bbb   2002-03-15   14

the condition is:
df$temp==15
matching raws are 1 and i-1:
I need something to select (only) rows where date=one month before the matching raws, so raws 3 and i. (the variable name has more than one level) Thanks



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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Thu Aug 18 22:53:43 2005

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