On Aug 26, 2010, at 10:35 AM, Niels Richard Hansen wrote:
>
>
> On 26/08/10 09.30, Dimitris Rizopoulos wrote:
>> I think you need an I(), i.e.,
>>
>> form <- ~ I(a > 1) - 1
>
> Yes, it solves the concrete problem, but does not really answer
> the question. Let me rephrase. Should the use of t
On 26/08/10 09.30, Dimitris Rizopoulos wrote:
I think you need an I(), i.e.,
form <- ~ I(a > 1) - 1
Yes, it solves the concrete problem, but does not really answer
the question. Let me rephrase. Should the use of terms like (a>1)
be discouraged in R and replaced by I(a>1) systematically, or
I think you need an I(), i.e.,
form <- ~ I(a > 1) - 1
I hope it helps.
Best,
Dimitris
On 8/26/2010 9:17 AM, Niels Richard Hansen wrote:
I have the following problem
mydata <- data.frame(a=1:3)
form <- ~ (a>1) - 1
model.matrix(form,mydata)
a > 1FALSE a > 1TRUE
1 1 0
2 0 1
3 0 1
...
Howeve
I have the following problem
mydata <- data.frame(a=1:3)
form <- ~ (a>1) - 1
model.matrix(form,mydata)
a > 1FALSE a > 1TRUE
1 1 0
2 0 1
3 0 1
...
However
model.matrix(update(terms(form)[1],~.-1),mydata)
(Intercept) a > 1 - 1TRUE
1
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