[R] How to convert a string to the column it represents in a dataframe, with a reproducible example

[Bert Gunter]

Inline below.

-- Bert

On Thu, Jan 17, 2013 at 3:02 PM, David Winsemius <dwinsemius at comcast.net> wrote:
>
> On Jan 17, 2013, at 2:26 PM, mtb954 at gmail.com wrote:
>
>> Hi David,
>>
>> I would like to have two objects, one containing the values in a column and the other containing the column's name.
>
> You have not addressed the question ... why? Where are you going with this?
>
>> Of course, that's easy to do manually, but I don't want to have to type out the name of the column more than once (thus, below, I have typed it once in quotes, and I am trying to find a programatic way to create the other object, without typing the column name again).
>
> I would think that this is be best way to proceed:
>
> x <- cars[ , "dist",  drop=FALSE]
>
> Now "x" is a data.frame (and inherits from the list-class)  and names(x) will return "dist" and the usual access methods would work.

... which, of course, begs the question: why bother. as you would do
the same with the original data frame.

-- Bert

>
> --
> David.
>>
>> Thank you for your help.
>>
>> Mark Na
>>
>>
>> On Thu, Jan 17, 2013 at 4:06 PM, David Winsemius <dwinsemius at comcast.net> wrote:
>>
>> On Jan 17, 2013, at 1:36 PM, mtb954 at gmail.com wrote:
>>
>> > Hello R-helpers,
>> >
>> > I have run the following lines of code:
>> >
>> > x<-"cars$dist"
>> > y<-noquote(x)
>> >
>> >
>> > Now y is a string containing the characters "cars$dist"
>> >
>> > My question....is there an R function (or combination of functions) that I
>> > can apply to y that will cause y to contain the numbers in cars$dist? Even
>> > better, can I do it without using noquote()?
>>
>> What is the goal of this effort?
>>
>> --
>>
>> David Winsemius
>> Alameda, CA, USA
>>
>>
>
> David Winsemius
> Alameda, CA, USA
>
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> and provide commented, minimal, self-contained, reproducible code.



-- 

Bert Gunter
Genentech Nonclinical Biostatistics

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