On Aug 26, 2010, at 6:10 PM, Jorge Ivan Velez wrote:
Hi Chipper,
Try
test.df[unlist(sort.v),]
That does work, and I suspect it is because data.frame converts
character vectors to factors by default. So this also works:
test.df[factor(c("Lake","Shoreline","Floodplain")), ]
But why? I must be reading the wrong help pages. I would have assumed
that the factor object was being read into the extract call as a
numeric which would not have resulted in the observed behavior. I do
not see in the Extract help page that factors offered as "i" arguments
are supposed to be matched to the first column of dataframes.
--
David.
HTH,
Jorge
On Thu, Aug 26, 2010 at 5:59 PM, chipmaney <> wrote:
I have a dataset I need to sort:
test.df<-data.frame(Zone=c("Floodplain", "Lake",
"Shoreline"),Cover=c(50,60,70))
However, I don't want it sorted ascending/descending but in an
order that I
define via a vector:
sort.v<-data.frame(c("Lake","Shoreline","Floodplain"))
I realize I could probably just create the vector of [factors] in
the order
I want, then assign the value:
sort.v$Cover<-test.df$Cover
However, this is inefficient. Is there source code or a
syntactical trick
that will do the same more efficiently? Note: I have investigated
order()
and sort(), but neither seems to have an argument for defining the
sorting
order.
Thanks in advance, Chipper
David Winsemius, MD
West Hartford, CT
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