[R] a weird "cut" question

[William Dunlap]

You could use quantile() to create the breakpoints
  > x <- c(47677, 47602, 47678, 47905, 47909, 47906, 47605, 47673, 47607)
  > cutX <- cut(x, breaks=quantile(x, (0:3)/3), include.lowest=TRUE)
  > cutX
  [1] (4.77e+04,4.78e+04] [4.76e+04,4.77e+04] (4.77e+04,4.78e+04] (4.78e+04,4.79e+04]
  [5] (4.78e+04,4.79e+04] (4.78e+04,4.79e+04] [4.76e+04,4.77e+04] (4.77e+04,4.78e+04]
  [9] [4.76e+04,4.77e+04]
  Levels: [4.76e+04,4.77e+04] (4.77e+04,4.78e+04] (4.78e+04,4.79e+04]
  > table(cutX)
  cutX
  [4.76e+04,4.77e+04] (4.77e+04,4.78e+04] (4.78e+04,4.79e+04] 
                  3                   3                   3

This will fail if there are only 2 distinct values in the dataset.

Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com 

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of Erin Hodgess
> Sent: Wednesday, December 07, 2011 7:15 PM
> To: R help
> Subject: [R] a weird "cut" question
> 
> Dear R People:
> 
> I have the following data:
> 
> > ail.df[,1]
> [1] 47677 47602 47678 47905 47909 47906 47605 47673 47607
> > cut(ail.df[,1],breaks=3)
> [1] (4.76e+04,4.77e+04] (4.76e+04,4.77e+04] (4.76e+04,4.77e+04]
> [4] (4.78e+04,4.79e+04] (4.78e+04,4.79e+04] (4.78e+04,4.79e+04]
> [7] (4.76e+04,4.77e+04] (4.76e+04,4.77e+04] (4.76e+04,4.77e+04]
> Levels: (4.76e+04,4.77e+04] (4.77e+04,4.78e+04] (4.78e+04,4.79e+04]
> >
> so I have cut ail.df[,1] into 3 levels.  However, the second level
> never appears in the data set.
> 
> Is there a way to set cut such that every level appears, please?
> 
> thanks in advance,
> Sincerely,
> Erin
> 
> 
> --
> Erin Hodgess
> Associate Professor
> Department of Computer and Mathematical Sciences
> University of Houston - Downtown
> mailto: erinm.hodgess at gmail.com
> 
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