Bill is right on both points. My longer clumsier code is for
chickens who are afraid to change any more than they have to.
Don McKenzie
On 21-Jun-11, at 4:36 PM, <bill.venab...@csiro.au> wrote:
The point I would make is that for safety it's much better to use
FALSE rather than F. FALSE is a reserved word in R, F is a pre-set
variable, but can easily be changed at any time by the user.
Secondly, doesn't this do the same as yours:
readFF.csv <- function(..., stringsAsFactors = FALSE)
read.csv(..., stringsAsFactors = stringsAsFactors)
? (Warning: untested code...)
Personally, I much prefer stringsAsFactors = TRUE, but then that's
the way I was brought up...
Bill Venables.
-----Original Message-----
From: Don McKenzie [mailto:d...@u.washington.edu]
Sent: Wednesday, 22 June 2011 8:40 AM
To: Venables, Bill (CMIS, Dutton Park)
Cc: stevenkennedy2...@gmail.com; alina...@gmail.com; r-help@r-
project.org
Subject: Re: [R] converting character to numeric
I have to chime in here with a slight revision to read.csv(), for
those of us like me who have whined over time about
"stringsAsFactors".
(tested on my machine macOSX 10.6)
readFF.csv <-
function (file, header = TRUE, sep = ",", quote = "\"", dec = ".",
fill = TRUE, comment.char = "", ...)
read.table(file = file, header = header, sep = sep, quote = quote,
dec = dec, fill = fill, stringsAsFactors=F,comment.char =
comment.char, ...)
On 21-Jun-11, at 3:16 PM, <bill.venab...@csiro.au> wrote:
..or something like that. Without more details it is hard to know
just what is going on.
Firstly in R the object is a 'data frame' (or object of class
"data.frame" to be formal). There is no standard object in R
called a 'database'.
If you read in your data using read.csv, then mydata is going to be
a data frame. Character columns in the original .csv file will be
(most likely) factors in the R object. (This varies with how you
import it, though.) This means you will need to convert them to
character before you convert them to numeric. If they really are
character, this initial conversion will not do anything (good or
bad).
If you want to operate on the individual columns of the data frame,
then I would recommend you do it using something like:
mydata <- within(mydata, {
apples <- as.numeric(as.character(apples))
oranges <- as.numeric(as.character(oranges))
.......
})
Bill Venables.
-----Original Message-----
From: r-help-boun...@r-project.org [mailto:r-help-bounces@r-
project.org] On Behalf Of Steven Kennedy
Sent: Wednesday, 22 June 2011 6:52 AM
To: Alina Sheyman
Cc: r-help@r-project.org
Subject: Re: [R] converting character to numeric
You need:
mydata$apples<-as.numeric(mydata$apples)
On Wed, Jun 22, 2011 at 6:38 AM, Alina Sheyman <alina...@gmail.com>
wrote:
I'm trying to convert data from character to numeric.
I've imported data as a csv file, I'm assuming that the import is a
database - are all the columns in a database considered
"vectors" and that
they can be operated on individually
Therefore I've tried the following
mydata <- as.numeric(mydata$apples)
when i then look at mydata again the named column is still in
"character"
format
if i do mydata2 <- as.numeric(mydata$apples)
the new object mydata2 is empty.
Am i missing something about the structure of R?
alina
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Science is organized skepticism in the reliability of expert opinion
-- Richard Feynman
Don McKenzie, Research Ecologist
Pacific WIldland Fire Sciences Lab
US Forest Service
Affiliate Professor
School of Forest Resources, College of the Environment
CSES Climate Impacts Group
University of Washington
phone: 206-732-7824
d...@uw.edu
Science is organized skepticism in the reliability of expert opinion
-- Richard Feynman
Don McKenzie, Research Ecologist
Pacific WIldland Fire Sciences Lab
US Forest Service
Affiliate Professor
School of Forest Resources, College of the Environment
CSES Climate Impacts Group
University of Washington
phone: 206-732-7824
d...@uw.edu
______________________________________________
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
