Hi,
You can follow this example:
test <- structure(list(V1 = c(0L, 1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 3L,
3L, 3L, 3L, 3L, 4L, 4L, 4L, 4L, 4L), V2 = c(12L, 10L, 4L, 6L,
7L, 13L, 21L, 23L, 20L, 18L, 17L, 16L, 27L, 33L, 11L, 8L, 19L,
16L, 9L)), .Names = c("V1", "V2"), class = "data.frame", row.names =
c(NA,-19L))
tapply(grid1$V2, grid1$V1, sum)
0 1 2 3 4
12 40 64 111 63
HTH
Pascal
Le 04/12/2012 16:59, T Bal a ?crit :
Hi,
I have the following data:
0 12
1 10
1 4
1 6
1 7
1 13
2 21
2 23
2 20
3 18
3 17
3 16
3 27
3 33
4 11
4 8
4 19
4 16
4 9
In this data file I would like to sum the numbers of second column which
belong to the same number in the first column.
So the output would be:
0 12
1 40
2 64
3 111
etc.
Thank you.
Kind regards,
T. Bal
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