[R] subset dataframe/list

[Cecilia Carmo]

It doesn't work. b1 was substituted by NA's with this 
message:
Warning message:
NAs introduced by coercion

I will see in the webpage that you mentioned.

Thanks,

Cecília

Em Mon, 1 Jun 2009 13:23:12 -0400
  David Winsemius <dwinsemius at comcast.net> escreveu:
> 
> On Jun 1, 2009, at 1:01 PM, Cecilia Carmo wrote:
> 
>> Hi R-helpers!
>>
>> I have the following object:
>>> head(coeficientes)
>>    caedois           b1           b2           b3
>> 1       1    0,033120395 -20,29478338 -0,274638864
>> 2       2   -0,040629634  74,54239889 -0,069958424
>> 3       5   -0,001116816   35,2398622  0,214327185
>> 4      10     0,171875
>> 5      14   0,007288399  40,06560548 -0,081828338
>> 6      15   0,027530346  0,969969409  0,102775555
>>
>> I´ve tried to subset it like this:
>>> coefSelected<-subset(coeficientes,"b1">0)
>> but it does nothing
>>
>> Then I’ve tried:
>>> coefSelected<-subset(coeficientes,b1>0)
>> But I´ve got the following
>> Warning message:
>> In Ops.factor(b1, 0) : > not meaningful for factors
> 
> So the b1 variable is a factor. How it got that way is 
>hard to  determine.
>>
>>
>> So I’ve tried:
>>> coefSelected<-subset(coeficientes,coeficientes$b1>0)
>> Warning message:
>> In Ops.factor(coeficientes$b1, 0) : > not meaningful for 
>>factors
>>
>> I´ve done
>>> mode(coeficientes)
>> [1] "list"
> 
> So coeficientes could be just a list or  more likely it 
>is a data.frame.
> 
> What happens if you convert b1 to numeric? Try this way:
> 
> coeficientes$b1 <- as.numeric( 
>as.character(coeficientes$b1) )
> 
> Then try subsetting.
> 
> See: 
>http://cran.r-project.org/doc/FAQ/R-FAQ.html#How-do-I-convert-factors-to-numeric_003f
> 
>>
>>
>> But I don´t know how to handle it!
>> Coul anyone help me?
>> Thanks,
>>
>> Cecília Carmo (Universidade de Aveiro – Portugal
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> 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.
> 
> David Winsemius, MD
> Heritage Laboratories
> West Hartford, CT
>