Bill is right on both points. My longer clumsier code is for
> 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:
[hidden email]]
> Sent: Wednesday, 22 June 2011 8:40 AM
> To: Venables, Bill (CMIS, Dutton Park)
> Cc:
[hidden email];
[hidden email]; 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, <
[hidden email]> 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:
[hidden email] [mailto:r-help-bounces@r-
>> project.org] On Behalf Of Steven Kennedy
>> Sent: Wednesday, 22 June 2011 6:52 AM
>> To: Alina Sheyman
>> Cc:
[hidden email]
>> 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 <
[hidden email]>
>> 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
>>>
>>> [[alternative HTML version deleted]]
>>>
>>> ______________________________________________
>>>
[hidden email] mailing list
>>>
https://stat.ethz.ch/mailman/listinfo/r-help>>> PLEASE do read the posting guide
http://www.R-project.org/posting->>> guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>
>> ______________________________________________
>>
[hidden email] mailing list
>>
https://stat.ethz.ch/mailman/listinfo/r-help>> PLEASE do read the posting guide
http://www.R-project.org/posting->> guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>> ______________________________________________
>>
[hidden email] mailing list
>>
https://stat.ethz.ch/mailman/listinfo/r-help>> PLEASE do read the posting guide
http://www.R-project.org/posting->> guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>
> 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
>
[hidden email]
>
>
>
>
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