[R] Which hist cell each value falls in?

[Doug Hill]

Thanks, guys! Doug


David Winsemius wrote:
> 
> 
> 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
>>
>> ______________________________________________
>> R-help at 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
> Heritage Laboratories
> West Hartford, CT
> 
> ______________________________________________
> R-help at 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.
> 
> 

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