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rpartitioningquantilehmiscquartile

Obtaining nice cuts in Hmisc with cut2 (without the [ ) signs )


I'm currently trying to neatly cut data with use of the Hmisc package, as in the example below:

dummy <- data.frame(important_variable=seq(1:1000))
require(Hmisc)
dummy$cuts <- cut2(dummy$important_variable, g = 4)

The produced cuts are correct with respect to the values:

  important_variable       cuts
1                  1 [  1, 251)
2                  2 [  1, 251)
3                  3 [  1, 251)
4                  4 [  1, 251)
5                  5 [  1, 251)
6                  6 [  1, 251)
> table(dummy$cuts)
[  1, 251) [251, 501) [501, 751) [751,1000] 
       250        250        250        250 

However, I would like for the data to be presented slightly differently. For instance instead of

[ 1, 251 )

[ 251, 501 )

I would prefer the notation

1 - 250

251 - 500

As I'm doing a lot of that on multiple variables I'm interested in a reproducible solution that would be easy to apply across multiple variables.


Edit

Following the discussion in comments, the solution would have to work on more messy variables, like x2 <- runif(100, 5.0, 7.5).


Solution

  • We could use gsubfn to remove the parentheses as well as change the numeric part by subtracting one from the second set of numbers

     library(gsubfn)
     v1 <- dummy$cuts
     v1New <-  gsubfn('\\[\\s*(\\d+),\\s*(\\d+)[^0-9]+', ~paste0(x, '-', 
                         as.numeric(y)-1), as.character(v1))
     table(v1New)
     # 1-250 251-500 501-750 751-999 
     #  250     250     250     250 
    

    For the second case involving decimals, we need to match the numbers along with decimals and capture those groups by placing them in parentheses (([0-9.]+), (\\d+\\.\\d+)). We change the second set of capture group by converting to 'numeric' and subtracting 0.01 from it (as.numeric(y)-0.01). The \\s* denotes 0 or more spaces. The spaces was uneven in the format, so we had to use that instead of \\s+ which is 1 or more spaces.

     v2New <- gsubfn('\\[\\s*([0-9.]+),(\\d+\\.\\d+).*', ~paste0(x,
                     '-',as.numeric(y)-0.01), as.character(v2))
     table(v2New)
     v2New
     #5.00-5.59 5.60-6.12 6.13-6.71 6.72-7.49 
     #    25        25        25        25 
    

    data

     set.seed(24)
     x2 <- runif(100, 5.0, 7.5)
     v2 <- cut2(x2, g=4)