On 04/06/10 10:32, Petr PIKAL wrote:
One option:
t<- data.frame(x1=c(1,1,0,0,0,1), x2=c(0,0,0,1,0,1),
Count=c(523,23,2,45,3,433))
t.sum<- function(df, x1, x2) sum(df[df$x1==x1& df$x2==x2,]$Count)
[...]
If this is what Khan wants so
aggregate(t$Count, list(interaction(t$x1, t$x2)), sum)
Group.1 x
1 0.0 5
2 1.0 546
3 0.1 45
4 1.1 433
could be better option
Indeed it is better! Or even shorter with the formula interface:
aggregate(Count ~ x1+x2, data=t, sum)
# x1 x2 Count
# 1 0 0 5
# 2 1 0 546
# 3 0 1 45
# 4 1 1 433
Allan
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