在R中:重复数据帧的每个原始数据所需的次数(对于每一行可能不同)

Question

我有自己的解决方案来解决我的问题,但它涉及循环并且相对较慢.有什么方法可以更快地在R中使用 - 使用一些更高级的包？谢谢!

# My data frame:
d <- data.frame(ID=1:10,a = 1:10,b = 5:14)
# Desired number of repeats for each row:
freq = c(2,2,3,3,3,4,5,5,5,6)
# i.e., Raw 1 of d should be repeated 2 times
# Raw 10 of d should be repeated 6 times.

# My current solution - looping through unique values of freq:
d.long<-NULL
myrepeats=unique(freq)
for(i in myrepeats){
  onecount<-d[freq==i,]
  for(ii in 2:i){
    temp<-d[freq==i,]
    onecount<-rbind(onecount,temp)
  }
  d.long<-rbind(d.long,onecount)
}
d.long<-d.long[order(d.long$ID),]
(d.long)

Answer 1

您可以使用重复索引:

d.long <- d[rep(1:nrow(d), times=freq),]