我有10万个人
要创建一个包含"letters"
、"LETTERS"
和"0:9"
个字符的5个字符的ID,可能的唯一组合数是多少?
set.seed(0)
mydata<-data.frame(
ID=rep(NA,10^5),
Poids=rnorm(n=10^5,mean = 65,sd=5)
)
for (i in 1:nrow(mydata)){
mydata$ID[i]<-c(
paste(sample(c(0:9,LETTERS,letters),replace = F,size = 1),
sample(c(0:9,LETTERS,letters),replace = F,size = 1),
sample(c(0:9,LETTERS,letters),replace = F,size = 1),
sample(c(0:9,LETTERS,letters),replace = F,size = 1),
sample(c(0:9,LETTERS,letters),replace = F,size = 1),sep = "")
)
}
table(duplicated(mydata$ID))
FALSE TRUE
99996 4