In R：重複數據幀的每個原始數據所需的次數（對於每一行可能不同）

Question

我有我自己的解決方案tp我的問題，但它涉及循環並且相對較慢。任何方式在R中更快地使用它 - 使用一些更高級的軟件包？ 謝謝！

# 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

您可以使用重複指數：

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