On May 14, 2011, at 2:27 PM, William Dunlap wrote:
You could use findInterval() along with a trick with c(rbind(...)):
i <- findInterval(x=df.1$time, vec=c(rbind(df.2$from, df.2$to)))
i
[1] 1 1 1 2 3 3 3 5 5 6
That's nice. I was working on a slightly different "trick"
findInterval( df.1[,1],t(df.2[,1:2]))
[1] 1 1 1 2 3 3 3 5 5 6
I was then trying to get the right indices with (.)'%%' 2 and (.) '%/
%' 2
The even-valued outputs would map to NA's, the odds
to value[(i+1)/2], but you can use the c(rbind(...)) trick again:
c(rbind(df.2$value, NA))[i]
[1] 1 1 1 NA 3 3 3 5 5 NA
I'd like to understand that. Maybe, maybe... ah, got it. At first I
didn't realize those were the final answers since they looked like
indices. My t(.) trick doesn't generalize as well.
My earlier suggestion tht two merges woul do it was based on my
erroneous interpretation of the example, since I thought the task was
to match on the end points of the intervals.
Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com
-----Original Message-----
From: r-help-boun...@r-project.org
[mailto:r-help-boun...@r-project.org] On Behalf Of René Mayer
Sent: Saturday, May 14, 2011 11:06 AM
To: David Winsemius
Cc: r-help@r-project.org
Subject: Re: [R] how to merge within range?
thanks David and Ian,
let me make a better example as the first one was flawed
df.1=data.frame(round((1:10)*100+rnorm(10)), value=NA)
names(df.1) = c("time", "value")
df.1
time value
1 101 NA
2 199 NA
3 301 NA
4 401 NA
5 501 NA
6 601 NA
7 700 NA
8 800 NA
9 900 NA
10 1000 NA
# from and to define ranges within time,
# note that from and to may not match the numbers given in time
df.2=data.frame(from=c(99,500,799),to=c(303,702,950), value=c(1,3,5))
df.2
from to value
1 99 303 1
2 500 702 3
3 799 950 5
what I want is:
time value
1 101 1
2 199 1
3 301 1
4 401 NA
5 501 3
6 601 3
7 700 3
8 800 5
9 900 5
10 1000 NA
@David I don't know what you mean by 2 merges,
René
Zitat von "David Winsemius" <dwinsem...@comcast.net>:
On May 14, 2011, at 9:16 AM, Ian Gow wrote:
If I assume that the third column in data.frame.2 is named
"val" then in
SQL terms it _seems_ you want
SELECT a.time, b.val FROM data.frame.1 AS a LEFT JOIN
data.frame.2 AS b ON
a.time BETWEEN b.start AND b.end;
Not sure how to do that elegantly using R subsetting/merge,
Huh? It's just two merge()'s (... once you fix the error in
the example.)
--
David
but you might
try a package that allows you to use SQL, such as sqldf.
On 5/14/11 8:03 AM, "David Winsemius"
<dwinsem...@comcast.net> wrote:
On May 14, 2011, at 8:12 AM, René Mayer wrote:
Hello,
how can one merge
And what happened when you typed:
?merge
two data frames when in the second data frame one column
defines the
start values
and another defines the end value of the to be merged range.
data.frame.1
time ...
13
24
35
46
55
...
data.frame.2
start end
24 37 ?h? ?
...
should result in this
13 NA
24 ?h?
35 ?h?
46 NA
55
?
And _why_ would that be?
thanks,
René
______________________________________________
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PLEASE do read the posting guide
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David Winsemius, MD
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______________________________________________
R-help@r-project.org mailing list
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PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
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.
David Winsemius, MD
West Hartford, CT
______________________________________________
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
