Dear R users:
I have a small test dataframe as the follows :
math = c(80,75,70,65,65,70)
reading = c(65,70,88,NA,90,NA)
id = c('001','001','001','002','003','003')
score = data.frame(id, reading, math)
> score
id reading math
1 001 65 80
2 001 70 75
3 001 88 70
4 002 NA 65
5 003 90 65
6 003 NA 70
Could someone advise me tips about how to select the last row from
each id group of 001, 002, & 003?
In other words, the rows I need are :
id reading math
3 001 88 70
4 002 NA 65
6 003 NA 70
I tried function sebset but could not go very far. Thanks !
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