[R] to append a column to a data frame, has I use loop/if in my case?
josh.m.ulrich at gmail.com
Tue Jan 18 16:22:06 CET 2011
Please do not cross post: http://stackoverflow.com/q/4720076/271616
At the minimum, it would be polite to respond here with the answer you
accepted on Stack Overflow.
Joshua Ulrich | FOSS Trading: www.fosstrading.com
On Mon, Jan 17, 2011 at 8:59 AM, Daniel Wu <daniel_wu_r at 163.com> wrote:
> y is like
> days price regular
> 1 14990 0.16149463 0
> 2 14989 1.69519358 0
> 3 14988 1.57821998 0
> 4 14987 0.47614311 0
> 5 14986 0.87016180 0
> 6 14985 2.55679229 0
> 7 14984 0.89753533 0
> the output I want:
> have another column appended to y, whose value is the max price in the recent 2 **regular** weeks.
> So if the current row is today, then get the max price of the past 14 days (including today) if the last 2 week are regular weeks, if one of the last 2 weeks is not regular week, then I need to go back further to find the max price, as I need the max price for the last 2 **regular** weeks. How can I do that? Or I have to use loop/if to do it?
> BTW, why the days is like 14990,14989, after cbind(days,price,regular)? before the cbind, days is like the format "2010-12-23".
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