On Sep 13, 2011, at 1:17 PM, bradford wrote:
With the help of Andrie on StackOverflow.com, I was able to learn
about
ddply. I have another question that is more trivial and cannot seem
to find
help on IRC and do not want to bother Andrie again.
It's doubtful that he would have considered it a bother. Just post a
question and anyone up for rep points could do it. I certainly haven't
noticed that Andrie is slacking off despite his 14+K points.
I can't seem to figure
out what to google for, so I thought I'd ask here.
I have:
library(plyr)
df_diff <- ddply(df, .(SOURCE), summarize,
TIME_DIFF=-unclass(diff(REQUEST_DATE)))
df_diff
SOURCE TIME_DIFF
1 A 7.55
2 A 5.55
3 A 3.40
4 D 35.00
5 D 563.00
6 D 37.00
7 D 35.00
8 D 996.00
... with a lot more records.
I want to essentially sort SOURCE asc, TIME_DIFF asc and output the
top 15
lowest TIME_DIFFS for each SOURCE. How do I do this?
You might (I say "might" in the absence of a reproducible example for
testing) do this with ave:
df_diff[ with( df.diff, ave(TIME_DIFF, SOURCE , FUN= order) < 16), ]
Also, what is the data type of df_diff called so that I can look
into it
some more?
The second letter in a **ply call tells you. if it's a "d", then it
returns a dataframe. First letter is input class, second is output.
[[alternative HTML version deleted]]
_____________________________________________
David Winsemius, MD
West Hartford, CT
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
