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For a simple example, to "bin" 1000 (continuous value) datapoints in 10 bins (categories), with 100 datapoints in each bin:

x <- rnorm(1000, mean=0, sd=50)

# Next, let's say we want to create ten bins 
# with equal number of observations (100), in each bin:
bins <- 10
cutpoints <- quantile(x,(0:bins)/bins)

# The cutpoints variable 
# holds a vector of the cutpoints used to bin the data.   

# Finally we perform the binning to form the categories variable:

 binned <- cut(x,cutpoints,include.lowest=TRUE)
 summary(binned)
   [-152,-61]     (-61,-40]   (-40,-23.9] 
          100           100           100 
(-23.9,-10.2]  (-10.2,2.86]   (2.86,15.4] 
          100           100           100 
  (15.4,25.9]   (25.9,44.1]   (44.1,64.7] 
          100           100           100 
   (64.7,186] 
          100

As you can see, the last summary code gives you the number of x-values in each bin, (ie: 100 row values).

my Q:
How do you display the actual 100 x-values inside every bin PLUS its x row # (or rowname)??

What is the actual R-code
to get a 3-column data frame, (cols: Bin, Rowname and Values) structured like this?:

       Bin Rowname  Values
[-152,-61]  [25] -78.2  
            [28] -82.1  
            [75] -99.7 etc.....  

(-61,-40]    [18]-45.0  
             [26]-68.4 etc....

thanks!

user39150
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1 Answers1

3

You already have done everything you need, except wrap it into a data.frame

head(data.frame(Values=x, Bin=binned, Rowname=seq_along(x))[order(binned), ])
#       Values          Bin Rowname
# 2  -66.88718 [-189,-64.7]       2
# 5  -99.08521 [-189,-64.7]       5
# 8  -95.06063 [-189,-64.7]       8
# 10 -95.04592 [-189,-64.7]      10
# 15 -78.48819 [-189,-64.7]      15
# 28 -78.49396 [-189,-64.7]      28

You don't need a column for rownames though, since data.frame keep a rowname attribute, ie rownames(yourData)

Rorschach
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