R Under development (unstable) (2024-06-25 r86831 ucrt) -- "Unsuffered Consequences"
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> library("foreign")
> df <- read.arff("contact-lenses.arff")
> summary(df)
             age       spectacle-prescrip astigmatism tear-prod-rate
 pre-presbyopic:8   hypermetrope:12       no :12      normal :12    
 presbyopic    :8   myope       :12       yes:12      reduced:12    
 young         :8                                                   
 contact-lenses
 hard: 4       
 none:15       
 soft: 5       
> str(df)
'data.frame':	24 obs. of  5 variables:
 $ age               : Factor w/ 3 levels "pre-presbyopic",..: 3 3 3 3 3 3 3 3 1 1 ...
 $ spectacle-prescrip: Factor w/ 2 levels "hypermetrope",..: 2 2 2 2 1 1 1 1 2 2 ...
 $ astigmatism       : Factor w/ 2 levels "no","yes": 1 1 2 2 1 1 2 2 1 1 ...
 $ tear-prod-rate    : Factor w/ 2 levels "normal","reduced": 2 1 2 1 2 1 2 1 2 1 ...
 $ contact-lenses    : Factor w/ 3 levels "hard","none",..: 2 3 2 1 2 3 2 1 2 3 ...
> q()
> proc.time()
   user  system elapsed 
   0.31    0.06    0.31