# R-program for Supplementary Exercise 3.14 of IPS7e

names <- read.csv("r:/Chapter 3/ex03_014.csv")
set.seed(22092015)
sample(names[["name"]])
# select 20 names only
set.seed(22092015)
sample(names[["name"]], 20)
# note: the sample function has vector argument, see Exercise 1.51 for other
# ways to work with vector arguments 

# alternative, and more general, method, using a column of random numbers
set.seed(22092015)
names$random <- runif(40)
# data frame sorted according to random
names.sorted <- names[order(names$random),]
names.sorted[1:20,]