Calculating median based on the group in long format

Question

I have formated my data in long

df1<-read.table(text=" ID   Temp    location
1   12  4
1   18  3
1   17  5
1   10  1
1   19  1
1   15  4
1   16  5
1   10  3
1   11  5
1   15  1
2   20  3
2   10  3
2   17  1
2   13  5
2   12  1
2   14  4
2   20  5
2   13  1
2   13  3
2   10  3
3   12  4
3   18  3
3   18  3
3   15  1
3   17  1
3   15  4
3   10  1
3   11  3
3   13  1
3   14  1",header=TRUE)

I want to calculate the median ( round up) based on Temp and location for 3 groups (Id). The question is what is the median for id1, id2,id3, if location=1. In other words, 10,19 and 15, give a median of 15 or for id2, we have 17,12 and 13, give a median of 13.5, roundup=14. and so on.

So I need to get this data:

AM1 15
AM2 14
AM3 14

Thanks for your help and sorry I was unable to show my effort.

Answer 1

You could also use data.table.

library(data.table)
setDT(df1)[location == 1, .(Median = base::round(median(as.numeric(Temp)))), by = .(ID = paste0(“AM”, ID))]