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## R code Here is the comment.
library("survival")
## Loading required package: splines
## Load dataset
data(pbc)
## Examine first rows.
head(pbc, n = 10)
## id time status trt age sex ascites hepato spiders edema bili chol
## 1 1 400 2 1 58.77 f 1 1 1 1.0 14.5 261
## 2 2 4500 0 1 56.45 f 0 1 1 0.0 1.1 302
## 3 3 1012 2 1 70.07 m 0 0 0 0.5 1.4 176
## 4 4 1925 2 1 54.74 f 0 1 1 0.5 1.8 244
## 5 5 1504 1 2 38.11 f 0 1 1 0.0 3.4 279
## 6 6 2503 2 2 66.26 f 0 1 0 0.0 0.8 248
## 7 7 1832 0 2 55.53 f 0 1 0 0.0 1.0 322
## 8 8 2466 2 2 53.06 f 0 0 0 0.0 0.3 280
## 9 9 2400 2 1 42.51 f 0 0 1 0.0 3.2 562
## 10 10 51 2 2 70.56 f 1 0 1 1.0 12.6 200
## albumin copper alk.phos ast trig platelet protime stage
## 1 2.60 156 1718 137.95 172 190 12.2 4
## 2 4.14 54 7395 113.52 88 221 10.6 3
## 3 3.48 210 516 96.10 55 151 12.0 4
## 4 2.54 64 6122 60.63 92 183 10.3 4
## 5 3.53 143 671 113.15 72 136 10.9 3
## 6 3.98 50 944 93.00 63 NA 11.0 3
## 7 4.09 52 824 60.45 213 204 9.7 3
## 8 4.00 52 4651 28.38 189 373 11.0 3
## 9 3.08 79 2276 144.15 88 251 11.0 2
## 10 2.74 140 918 147.25 143 302 11.5 4
## summarize
summary(pbc)
## id time status trt age
## Min. : 1 Min. : 41 Min. :0.00 Min. :1.00 Min. :26.3
## 1st Qu.:105 1st Qu.:1093 1st Qu.:0.00 1st Qu.:1.00 1st Qu.:42.8
## Median :210 Median :1730 Median :0.00 Median :1.00 Median :51.0
## Mean :210 Mean :1918 Mean :0.83 Mean :1.49 Mean :50.7
## 3rd Qu.:314 3rd Qu.:2614 3rd Qu.:2.00 3rd Qu.:2.00 3rd Qu.:58.2
## Max. :418 Max. :4795 Max. :2.00 Max. :2.00 Max. :78.4
## NA's :106
## sex ascites hepato spiders edema
## m: 44 Min. :0.00 Min. :0.00 Min. :0.00 Min. :0.000
## f:374 1st Qu.:0.00 1st Qu.:0.00 1st Qu.:0.00 1st Qu.:0.000
## Median :0.00 Median :1.00 Median :0.00 Median :0.000
## Mean :0.08 Mean :0.51 Mean :0.29 Mean :0.101
## 3rd Qu.:0.00 3rd Qu.:1.00 3rd Qu.:1.00 3rd Qu.:0.000
## Max. :1.00 Max. :1.00 Max. :1.00 Max. :1.000
## NA's :106 NA's :106 NA's :106
## bili chol albumin copper
## Min. : 0.30 Min. : 120 Min. :1.96 Min. : 4.0
## 1st Qu.: 0.80 1st Qu.: 250 1st Qu.:3.24 1st Qu.: 41.2
## Median : 1.40 Median : 310 Median :3.53 Median : 73.0
## Mean : 3.22 Mean : 370 Mean :3.50 Mean : 97.6
## 3rd Qu.: 3.40 3rd Qu.: 400 3rd Qu.:3.77 3rd Qu.:123.0
## Max. :28.00 Max. :1775 Max. :4.64 Max. :588.0
## NA's :134 NA's :108
## alk.phos ast trig platelet
## Min. : 289 Min. : 26.4 Min. : 33.0 Min. : 62
## 1st Qu.: 872 1st Qu.: 80.6 1st Qu.: 84.2 1st Qu.:188
## Median : 1259 Median :114.7 Median :108.0 Median :251
## Mean : 1983 Mean :122.6 Mean :124.7 Mean :257
## 3rd Qu.: 1980 3rd Qu.:151.9 3rd Qu.:151.0 3rd Qu.:318
## Max. :13862 Max. :457.2 Max. :598.0 Max. :721
## NA's :106 NA's :106 NA's :136 NA's :11
## protime stage
## Min. : 9.0 Min. :1.00
## 1st Qu.:10.0 1st Qu.:2.00
## Median :10.6 Median :3.00
## Mean :10.7 Mean :3.02
## 3rd Qu.:11.1 3rd Qu.:4.00
## Max. :18.0 Max. :4.00
## NA's :2 NA's :6
## Examine dimensions
dim(pbc)
## [1] 418 20
## Examine the type (class) of objects
class(pbc)
## [1] "data.frame"
## assign a variable to a new object
timeTemp <- pbc$time
class(timeTemp)
## [1] "integer"
dim(timeTemp)
## NULL