As everyone has been telling you, as.factor().
If you like the mutate approach, you can call as.factor(test$subject)
to convert it.
Here's a one-liner with reproducible data.
testdata <- structure(list(subject = structure(1:6, .Label = c("001-002",
"002-003", "003-004", "004-005", "005-006", "006-007"), class = "factor"),
group = structure(c(1L, 1L, 1L, 2L, 2L, 2L), .Label = c("boys",
"girls"), class = "factor"), wk1 = c(2L, 7L, 9L, 5L, 2L,
1L), wk2 = c(3L, 6L, 4L, 7L, 6L, 4L), wk3 = c(4L, 5L, 6L,
8L, 3L, 7L), wk4 = c(5L, 4L, 1L, 9L, 8L, 4L)), .Names = c("subject",
"group", "wk1", "wk2", "wk3", "wk4"), class = "data.frame", row.names = c(NA,
-6L))
testdata$subject <- as.factor(substring(as.character(testdata$subject), 1, 3))
> testdata
subject group wk1 wk2 wk3 wk4
1 001 boys 2 3 4 5
2 002 boys 7 6 5 4
3 003 boys 9 4 6 1
4 004 girls 5 7 8 9
5 005 girls 2 6 3 8
6 006 girls 1 4 7 4
> str(testdata)
'data.frame': 6 obs. of 6 variables:
$ subject: Factor w/ 6 levels "001","002","003",..: 1 2 3 4 5 6
$ group : Factor w/ 2 levels "boys","girls": 1 1 1 2 2 2
$ wk1 : int 2 7 9 5 2 1
$ wk2 : int 3 6 4 7 6 4
$ wk3 : int 4 5 6 8 3 7
$ wk4 : int 5 4 1 9 8 4
Sarah
On Fri, Mar 4, 2016 at 1:00 PM, KMNanus <kmna...@gmail.com> wrote:
>
> Here’s the dataset I’m working with, called test -
>
> subject group wk1 wk2 wk3 wk4 place
> 001-002 boys 2 3 4 5
> 002-003 boys 7 6 5 4
> 003-004 boys 9 4 6 1
> 004-005 girls 5 7 8 9
> 005-006 girls 2 6 3 8
> 006-007 girls 1 4 7 4
>
>
> if I call mutate(test, place = substr(subject,1,3), “001 is the first
> observation in the place column
>
> But it’s a character and “subject” is a factor. I need place to be a factor,
> too, but I need the observations to be ONLY the first three numbers of
> “subject.”
>
> Does that make my request more understandable?
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