Categorizing a variable in R using the cut command



retinol$age
  [1] 64 76 38 40 72 40 65 58 35 55 66 40 57 66 66 64 62 75 68 57 56 30 34 53 60 50 62 61 65 71 43 33 74 41
 [35] 56 44 37 37 39 37 53 66 58 31 49 75 62 56 69 50 50 72 60 55 43 29 44 48 38 33 56 65 48 66 78 65 72 31
 [69] 74 61 83 46 62 56 33 45 41 73 31 50 65 35 42 19 37 44 36 53 69 74 70 56 77 73 43 41 22 44 51 46 25 69
[103] 69 58 77 67 37 47 60 49 83 56 39 41 37 66 55 49 31 64 57 42 40 73 37 43 66 26 45 74 49 41 74 38 83 70
[137] 39 65 72 46 46 51 39 33 49 44 69 52 82 46 25 54 70 35 46 70 71 59 42 46 37 39 43 23 45 63 44 43 33 35
[171] 50 50 59 38 60 54 71 48 49 27 27 75 45 35 56 41 48 48 32 38 52 40 44 70 55 48 38 49 36 64 49 49 43 33
[205] 38 36 33 47 53 41 36 32 57 42 37 52 45 42 42 41 41 26 70 44 46 22 46 32 27 52 42 34 36 59 75 43 56 48
[239] 34 37 41 74 73 53 74 77 39 29 37 47 64 36 42 64 38 39 40 29 71 45 63 46 75 46 44 24 32 66 43 73 54 44
[273] 55 70 32 33 49 69 38 34 49 40 41 62 28 78 67 51 29 36 43 55 54 32 65 41 60 73 71 47 35 34 41 33 73 67
[307] 66 44 36 48 46 45 49 31 45

retinol$agecat1<-cut(retinol$age, c(0,20,30,40,50,60,90), right=T, labels=c("0 to 20", "21 to 30", "31 to 40", "41 to 50", "51 to 60", "61 to 90"))

[1] (60,90] (60,90] (30,40] (30,40] (60,90] (30,40] (60,90] (50,60] (30,40] (50,60] (60,90] (30,40]
 [13] (50,60] (60,90] (60,90] (60,90] (60,90] (60,90] (60,90] (50,60] (50,60] (20,30] (30,40] (50,60]
 [25] (50,60] (40,50] (60,90] (60,90] (60,90] (60,90] (40,50] (30,40] (60,90] (40,50] (50,60] (40,50]
 [37] (30,40] (30,40] (30,40] (30,40] (50,60] (60,90] (50,60] (30,40] (40,50] (60,90] (60,90] (50,60]
 [49] (60,90] (40,50] (40,50] (60,90] (50,60] (50,60] (40,50] (20,30] (40,50] (40,50] (30,40] (30,40]
 [61] (50,60] (60,90] (40,50] (60,90] (60,90] (60,90] (60,90] (30,40] (60,90] (60,90] (60,90] (40,50]
 [73] (60,90] (50,60] (30,40] (40,50] (40,50] (60,90] (30,40] (40,50] (60,90] (30,40] (40,50] (0,20] 
 [85] (30,40] (40,50] (30,40] (50,60] (60,90] (60,90] (60,90] (50,60] (60,90] (60,90] (40,50] (40,50]
 [97] (20,30] (40,50] (50,60] (40,50] (20,30] (60,90] (60,90] (50,60] (60,90] (60,90] (30,40] (40,50]
[109] (50,60] (40,50] (60,90] (50,60] (30,40] (40,50] (30,40] (60,90] (50,60] (40,50] (30,40] (60,90]
[121] (50,60] (40,50] (30,40] (60,90] (30,40] (40,50] (60,90] (20,30] (40,50] (60,90] (40,50] (40,50]
[133] (60,90] (30,40] (60,90] (60,90] (30,40] (60,90] (60,90] (40,50] (40,50] (50,60] (30,40] (30,40]
[145] (40,50] (40,50] (60,90] (50,60] (60,90] (40,50] (20,30] (50,60] (60,90] (30,40] (40,50] (60,90]
[157] (60,90] (50,60] (40,50] (40,50] (30,40] (30,40] (40,50] (20,30] (40,50] (60,90] (40,50] (40,50]
[169] (30,40] (30,40] (40,50] (40,50] (50,60] (30,40] (50,60] (50,60] (60,90] (40,50] (40,50] (20,30]
[181] (20,30] (60,90] (40,50] (30,40] (50,60] (40,50] (40,50] (40,50] (30,40] (30,40] (50,60] (30,40]
[193] (40,50] (60,90] (50,60] (40,50] (30,40] (40,50] (30,40] (60,90] (40,50] (40,50] (40,50] (30,40]
[205] (30,40] (30,40] (30,40] (40,50] (50,60] (40,50] (30,40] (30,40] (50,60] (40,50] (30,40] (50,60]
[217] (40,50] (40,50] (40,50] (40,50] (40,50] (20,30] (60,90] (40,50] (40,50] (20,30] (40,50] (30,40]
[229] (20,30] (50,60] (40,50] (30,40] (30,40] (50,60] (60,90] (40,50] (50,60] (40,50] (30,40] (30,40]
[241] (40,50] (60,90] (60,90] (50,60] (60,90] (60,90] (30,40] (20,30] (30,40] (40,50] (60,90] (30,40]
[253] (40,50] (60,90] (30,40] (30,40] (30,40] (20,30] (60,90] (40,50] (60,90] (40,50] (60,90] (40,50]
[265] (40,50] (20,30] (30,40] (60,90] (40,50] (60,90] (50,60] (40,50] (50,60] (60,90] (30,40] (30,40]
[277] (40,50] (60,90] (30,40] (30,40] (40,50] (30,40] (40,50] (60,90] (20,30] (60,90] (60,90] (50,60]
[289] (20,30] (30,40] (40,50] (50,60] (50,60] (30,40] (60,90] (40,50] (50,60] (60,90] (60,90] (40,50]
[301] (30,40] (30,40] (40,50] (30,40] (60,90] (60,90] (60,90] (40,50] (30,40] (40,50] (40,50] (40,50]

[313] (40,50] (30,40] (40,50]


describe (retinol$agecat1)

Factor 
         
x         (40,50] (60,90] (30,40] (50,60] (20,30] (0,20]
  Count     92.00    86.0   73.00    46.0    17.0   1.00
  Percent   29.21    27.3   23.17    14.6     5.4   0.32
Mode (40,50] 
Mode (40,50]

Introduction to the Analysis of Survival Data in the Presence of Competing Risks

 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4741409/