> On Aug 4, 2018, at 6:55 AM, David Hugh-Jones <[email protected]> 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
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