On Dec 18, 2009, at 2:57 AM, Jim Lemon wrote:
On 12/18/2009 06:35 AM, Doug Hill wrote:
Hi, all. I'm using hist() to obtain a vector of break values in an
interval.
I then want to be able to identify which cell any value from
another vector
falls in.
E.g. applying
breaks
[1] -3.5 -3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0
to
x
[1] -3.74519666 -0.38183630 -1.22884247 -0.20971824 -0.30533939
-0.36271207
[7] -2.27513499 -2.23688653 -1.98827155 -1.48666274 -1.26155084
-0.15234555
[13] -0.09497287 0.34488440
would give
xcells
[1] 1 8 6 8 8 8 4 4 5 6 6 8 8 9
where:
x<= breaks[1] -> cell 1
breaks[1]< x<= breaks[2] -> cell 2
breaks[2]< x<= breaks[3] -> cell 3, etc.
> breaks <- scan()
1: -3.5 -3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0
13:
Read 12 items
> xcells <- scan()
1: -3.74519666 -0.38183630 -1.22884247 -0.20971824 -0.30533939
-0.36271207
7: -2.27513499 -2.23688653 -1.98827155 -1.48666274 -1.26155084
-0.15234555
13: -0.09497287 0.34488440
15:
Read 14 items
> breaks <- c(-Inf,breaks,Inf)
> findInterval(xcells, breaks)
[1] 1 8 6 8 8 8 4 4 5 6 6 8 8 9
--
David
Hi Doug,
The function below does more or less what you want, except that the
bins are numbered from zero (meaning that a value is below the range
of bins as x[1] is) to length(breaks) (meaning that a value is above
the range of bins).
whichBin<-function(x,breaks,right=TRUE) {
lenx<-length(x)
# any leftovers must be out of range
wb<-rep(lenx,lenx)
if(right) wb[x<=breaks[1]]<-0
else wb[x<breaks[1]]<-0
for(bin in 1:(length(breaks)-1)) {
if(right) wb[x>breaks[bin] & x<=breaks[bin+1]]<-bin
else wb[x>=breaks[bin] & x<breaks[bin+1]]<-bin
}
return(wb)
}
Jim
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David Winsemius, MD
Heritage Laboratories
West Hartford, CT
______________________________________________
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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.
