r-有没有更简单的方法来扩展data.frame

Question

我想组合data1和region。目前，我使用for...，结果为total_df。有什么更简单的方法吗？谢谢

data1 <- data.frame(category=c("a","b","c"),
amount=1:3)
region <- data.frame(country=c('US','UK'))

total_df <- data.frame()
for (country in region$country){
data1$region <- country
total_df <- rbind(total_df,data1)
}

Answer 1

是！

使用rep，代码被重构，如下所示：

data1 <- data.frame(category=rep(c("a","b","c"),2),
amount=rep(1:3,2),
country=c(rep("US",3),rep("UK",3)))
> data1
category amount country
1        a      1      US
2        b      2      US
3        c      3      US
4        a      1      UK
5        b      2      UK
6        c      3      UK