[R] strings as factors

[Alexander Nervedi]

Hi,
To be able to match cases with a benchmark I need to have a data.frame with 
a character id variable. however, I am surprised why this seems to be so 
hard. In fact I was  unable to succeed. Here is what I tried:

>test1 <-expand.grid(ID = 1:2, sex = c("male","female"))
>is(test1[,2])
[1] "factor"   "oldClass"
>test2 <-expand.grid(ID = 1:2, sex = c('male','female'))
>is(test2[,2])
[1] "factor"   "oldClass"
>test3 <-expand.grid(ID = 1:2, sex = I(c("male","female")))
>is(test3[,2])
[1] "factor"   "oldClass"
>test4 <-expand.grid(ID = 1:2, sex = I(c('male','female')))
>is(test4[,2])
[1] "factor"   "oldClass"
>options(stringsAsFactors = FALSE)
>options("stringsAsFactors")
$stringsAsFactors
[1] FALSE

>test5 <-expand.grid(ID = 1:2, sex = I(c('male','female')))
>is(test5[,2])
[1] "factor"   "oldClass"


is there anyway I can get sex to be a character?

Arnab

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