I think of the methods of as.data.frame as a helper functions for
data.frame and don't usually call as.data.frame directly. data.frame()
will call as.data.frame for each of its arguments and then put together the
the results into one big data.frame.
> for(method in
To me the interesting difference between matrix() and as.matrix() is
that as.matrix() retains the argument names as the rows names of the
result.
> tmp <- structure(1:3, names=letters[1:3])
> tmp
a b c
1 2 3
> matrix(tmp)
[,1]
[1,]1
[2,]2
[3,]3
> as.matrix(tmp)
[,1]
a1
b
On 2/6/19 12:27 PM, Jeff Newmiller wrote:
I have no idea about "why it is this way" but there are many cases
where I would rather have to use backticks around
syntactically-invalid names than deal with arbitrary rules for
mapping column names as they were supplied to column names as R wants
I have no idea about "why it is this way" but there are many cases where I
would rather have to use backticks around syntactically-invalid names than deal
with arbitrary rules for mapping column names as they were supplied to column
names as R wants them to be. From that perspective, making the
Consider the following:
set.seed(42)
X <- matrix(runif(40),10,4)
colnames(X) <- c("a","b","a:x","b:x") # Imitating the output
# of model.matrix().
D1 <- as.data.frame(X)
D2 <- data.frame(X)
names(D1)
[1] "a" "b" "a:x" "b:x"
names(D2)
[1] "a" "b"
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