我有一个看起来像这样的R数据框:
z = as.data.frame(list(Col1=c("a","c","e","g"),Col2=c("b","d","f","h"),Col3=c("1,2,5","3,5,7","9,8","1")))
> z
Col1 Col2 Col3
1 a b 1,2,5
2 c d 3,5,7
3 e f 9,8
4 g h 1
第三列是一个由逗号分隔的文本列。我希望将其转换为以下数据框:
a b 1
a b 2
a b 5
c d 3
c d 5
c d 7
e f 9
e f 8
g h 1
有人能建议一种使用apply完成这个任务的方法吗?我已经接近成功,但还不够完美。如果有更高效的方法也希望得到建议...
> apply(z,1,function(a){ids=strsplit(as.character(a[3]),",")[[1]];out<-c();for(id in ids){out<-rbind(out,c(a[1:2],id))};return(out)})
[[1]]
Col1 Col2
[1,] "a" "b" "1"
[2,] "a" "b" "2"
[3,] "a" "b" "5"
[[2]]
Col1 Col2
[1,] "c" "d" "3"
[2,] "c" "d" "5"
[3,] "c" "d" "7"
[[3]]
Col1 Col2
[1,] "e" "f" "9"
[2,] "e" "f" "8"
[[4]]
Col1 Col2
[1,] "g" "h" "1"