[R] which() in subset()

[Charles Stangor]

Thanks Dennis and Mike... I'm getting it!!!

Sent from my Android

Rui Barradas <ruipbarradas at sapo.pt> wrote:

>Hello,
>
>To know why, just evaluate the condition, with 't1$' before 'version_1':
>
>which(as.character(t1$version_1) %in% a) != 0
>[1] TRUE TRUE
>
>
>It allways evaluates to TRUE, therefore, subset() returns all rows.
>
>See if this isn't simpler than both of your forms.
>
>v2 <- subset(t1, version_1 %in% a)
>v2
>   id version_1
>1  1     100-1
>2  2     100-2
>
>The trick is to use %in% when doing multiple comparisons. With the 
>vector with length equal to the number of observations on the left hand 
>side.
>
>Hope this helps,
>
>Rui Barradas
>
>Em 13-07-2012 12:12, Charles Stangor escreveu:
>> Why does the subset not work in the which() version below?
>>
>> Thank you
>>
>>
>> v1 <- subset(t1,
>>   version_1==as.character("100-1")
>>   | version_1==as.character("100-2"))
>>
>> a<-c("100-1", "100-2")
>> v1 <- subset(t1, which(a==as.character(version_1)) != 0)
>>
>> 	[[alternative HTML version deleted]]
>>
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>