[R] For Loop help needed
Allan Engelhardt
allane at cybaea.com
Fri Jun 4 12:01:49 CEST 2010
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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