Hi Bill,
Great soluiton!
Just to add:
if values are not sorted (in this case, okay)
set.seed(434)
val1<- rnorm(1e5)
set.seed(28)
thresh1<- sample(1:20,1e2,replace=TRUE)
system.time(res11<- findInterval(thresh1,val1))
#Error in findInterval(thresh1, val1) :
# 'vec' must be sorted non-decreasingly
system.time(res<- findInterval(thresh1,sort(val1)))
# user system elapsed
# 0.012 0.000 0.014
system.time(res2<- sapply(thresh1,function(x) {sum(val1<x)}))
# user system elapsed
# 0.088 0.000 0.087
identical(res2,res)
#[1] TRUE
A.K.
----- Original Message -----
From: William Dunlap <wdun...@tibco.com>
To: Zhang Weiwu <zhangwe...@realss.com>; "r-help@r-project.org"
<r-help@r-project.org>
Cc:
Sent: Friday, September 13, 2013 10:44 AM
Subject: Re: [R] how to get values within a threshold
> findInterval(thresholds, values)
[1] 1 4 4 4 7
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 Zhang Weiwu
> Sent: Friday, September 13, 2013 3:14 AM
> To: r-help@r-project.org
> Subject: [R] how to get values within a threshold
>
>
> input:
>
> > values
> [1] 0.854400 1.648465 1.829830 1.874704 7.670915 7.673585 7.722619
>
> > thresholds
> [1] 1 3 5 7 9
>
> expected output:
>
> [1] 1 4 4 4 7
>
> That is, need a vector of indexes of the maximum value below the threshold.
>
> e.g.
> First element is "1", because value[1] is the largest below threshold "1".
> Second element is "4", because value[4] is the largest below threshold "3".
>
> The way I do it is:
>
> > sapply(1:length(threshold), function(x) { length(values[values <
> > threshold[x]])})
> [1] 1 4 4 4 7
>
> It just seem to me too long and stupid to be like R. Is it already the best
> way?
>
> Somehow I feel which() was designed for a purpose like this, but I couldn't
> figure out a way to apply which here.
>
> ______________________________________________
> 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.
______________________________________________
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.
______________________________________________
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.
