I'm not sure why this is happening:
tmp <- data.frame(
a = letters[1:2],
b=c(TRUE, FALSE),
stringsAsFactors = FALSE
)
idx <- matrix(c(1, 2, 2, 2), 2, byrow = TRUE)
tmp[idx]
[1] " TRUE" "FALSE"
Notice there is a space before the TRUE: " TRUE".
This space isn't happening purely because of coercion:
c("blah", TRUE, FALSE)
[1] "blah" "TRUE" "FALSE"
No space.
Obviously:
as.logical(tmp[idx])
[1] NA FALSE
which is why I think this might be a bug.
David
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> On Aug 4, 2018, at 6:55 AM, David Hugh-Jones <davidhughjones at gmail.com> wrote: > > I'm not sure why this is happening: > > tmp <- data.frame( > a = letters[1:2], > b=c(TRUE, FALSE), > stringsAsFactors = FALSE > ) > idx <- matrix(c(1, 2, 2, 2), 2, byrow = TRUE) > tmp[idx] > > [1] " TRUE" "FALSE" >>From ?"[.data.frame"Extract.data.frame {base} . . . Matrix indexing (x[i] with a logical or a 2-column integer matrix i) using [ is not recommended. For extraction, x is first coerced to a matrix. [...] Thus, something like as.matrix(tmp) happens converting every column to character. Dig deeper by reading ?matrix and see the paragraph on `as.matrix' under `Details'. HTH, Chuck
Yup, I worked it out in time... for future reference, as.matrix calls `format` on logicals, converting them to the form seen. On Sat, 4 Aug 2018 at 17:53, Berry, Charles <ccberry at ucsd.edu> wrote:> > > > On Aug 4, 2018, at 6:55 AM, David Hugh-Jones <davidhughjones at gmail.com> > wrote: > > > > I'm not sure why this is happening: > > > > tmp <- data.frame( > > a = letters[1:2], > > b=c(TRUE, FALSE), > > stringsAsFactors = FALSE > > ) > > idx <- matrix(c(1, 2, 2, 2), 2, byrow = TRUE) > > tmp[idx] > > > > [1] " TRUE" "FALSE" > > > > From ?"[.data.frame" > > Extract.data.frame {base} > . > . > . > Matrix indexing (x[i] with a logical or a 2-column integer matrix i) using > [ is not recommended. For extraction, x is first coerced to a matrix. > > [...] > > Thus, something like > > as.matrix(tmp) > > happens converting every column to character. Dig deeper by reading > > ?matrix > > and see the paragraph on `as.matrix' under `Details'. > > HTH, > > Chuck >-- Sent from Gmail Mobile [[alternative HTML version deleted]]