Hi Conrad,
On Wed, Sep 5, 2012 at 3:14 PM, Conradsb <csbal...@vt.edu> wrote:
> I currently have a data set in which gender is inputed as "Male" and "Female"
> , and I'm trying to convert this into "1" and "0".
This is usually not necessary, and makes things more confusing. "Male"
and "Female" is clear and self-explanatory: "0" and "1" are not.
>
> I found a website which reccomended using two commands:
>
> data$scode[data$sex=="M"] <- "1"
> data$scode[data$sex=="F"] <- "2"
Nope, "1" is the character 1, not the number 1 in R. Also, you said
the values were "Male" and "Female", not "F" and "M". To convert
"Male" to 1 and "Female" to 2 you can use
data$scode[data$sex=="Male"] <- 1
> data$scode[data$sex=="Female"] <- 2
Notice "Male" and "Female", instead of "M" and "F", and 1 and 2
instead of "1" and "2"
>
> to convert to numbers, and:
>
> data$scode <- factor(data$scode)
>
> to convert this variable to a factor.
No need to convert it to a factor first. Just use
data$sex <- factor(data$sex)
>
>
>
> My issue is that, after I use the first command, *only* the female values
> get converted to a number. I am left with a column filled with 2's and blank
> spaces.
Strange, especially if sex is actually "Male" and "Female", in which
case scode should be all NA. If you want to follow up on this, please
post the result of
dput(dat["sex"])
Instead of typing both lines of the first command, I copy and pasted
> the first line and changed the letter representing gender. I also made sure
> that both letters were exactly as they appear in the dataset.
>
> My questions are: is there any visible issue with my syntax, and are there
> any other methods to accomplish this?
In this case you don't actually need to convert to numeric. Just use
data$scode <- factor(scode)
If you really need to convert characters to numbers, it is often
convenient to use factors as intermediate steps, like this:
dat <- data.frame(sex=sample(c("Male", "Female"), 10, replace=TRUE))
dat$sex.n <- as.numeric(
as.character(
factor(
dat$sex,
levels = c("Female", "Male"),
labels = c("0", "1"))))
Best,
Ista
>
> I'm also very new to R, so complex syntax is beyond me.
>
> Conrad Baldner
>
>
>
> --
> View this message in context:
> http://r.789695.n4.nabble.com/Recoding-categorical-gender-variable-into-numeric-factors-tp4642316.html
> Sent from the R help mailing list archive at Nabble.com.
>
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