two apparent anomalies
(1)
a <- c("a", "b")
str(a)
chr [1:2] "a" "b"
b <- c(1,2) str(b)
num [1:2] 1 2
c <- data.frame(a, b) str(c)
'data.frame': 2 obs. of 2 variables: $ a: Factor w/ 2 levels "a","b": 1 2 $ b: num 1 2
mode(c$a)
[1] "numeric"
c2 <- data.frame(a, b, stringsAsFactors=FALSE) str(c2)
'data.frame': 2 obs. of 2 variables: $ a: chr "a" "b" $ b: num 1 2
mode(c2$a)
[1] "character" (2)
a <- c("a", "a", "b", "b", "c")
levels(as.factor(a))
[1] "a" "b" "c"
b <- a[1:3] b
[1] "a" "a" "b"
levels(as.factor(b))
[1] "a" "b"
a <- as.factor(a) a
[1] a a b b c Levels: a b c
a[1:3]
[1] a a b Levels: a b c On Sat, Jan 22, 2011 at 9:16 AM, analyst41 at hotmail.com
<analyst41 at hotmail.com> wrote:
(1)
a = c("a","b")
mode(a)
[1] "character"
b = c(1,2) mode(b)
[1] "numeric"
c = data.frame(a,b) mode(c$a)
[1] "numeric" (2)
a = c("a","a","b","b","c")
levels(as.factor(a))
[1] "a" "b" "c"
levels(as.factor(a[1:3]))
[1] "a" "b"
a = as.factor(a) levels(a)
[1] "a" "b" "c"
levels(a[1:3])
[1] "a" "b" "c" Any explanation would be helpful. ?Thanks.
Sarah Goslee http://www.functionaldiversity.org