[R] Creating Dummy Var in R for regression?

[Bert Gunter]

Just commenting on the email subject, not the content (which you have
already been helped with): there is no need to *ever* create a dummy
variable for regression in R if what you mean by this is what is
conventionally meant. R will create the model matrix with appropriate
"dummy variables" for factors as needed. See ?contrasts and ?C for
relevant details and/or consult an appropriate R tutorial.

Of course, if this is not what you meant, than ignore.

Cheers,
Bert


Bert Gunter

"The trouble with having an open mind is that people keep coming along
and sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )


On Fri, Aug 5, 2016 at 1:49 PM,  <ruipbarradas at sapo.pt> wrote:
> Hello,
>
> Your ifelse will never work because
> reasons$salutation== "Mr" & reasons$salutation=="Father" is always FALSE
> and so is reasons$salutation=="Mrs" & reasons$salutation=="Miss".
> Try instead | (or), not & (and).
>
> Hope this helps,
>
> Rui Barradas
>
>
>
> Citando Shivi Bhatia <shivipmp82 at gmail.com>:
>
>> Dear Team,
>>
>> I need help with the below code in R:
>>
>> gender_rec<- c('Dr','Father','Mr'=1, 'Miss','MS','Mrs'=2, 3)
>>
>> reasons$salutation<- gender_rec[reasons$salutation].
>>
>> This code gives me the correct output but it overwrites the
>> reason$salutation variable. I need to create a new variable gender to
>> capture gender details and leave salutation as it is.
>>
>> i tried the below syntax but it is converting all to 1.
>>
>> reasons$gender<- ifelse(reasons$salutation== "Mr" & reasons$salutation==
>> "Father","Male", ifelse(reasons$salutation=="Mrs" & reasons$salutation==
>> "Miss","Female",1))
>>
>> Please suggest.
>>
>>         [[alternative HTML version deleted]]
>>
>> ______________________________________________
>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.htmland provide commented,
>> minimal, self-contained, reproducible code.
>
>
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.