R help - Apr 2011 - How to remove the double or single quote from a string (unquote?)?

Is there a function to get a string without a pair of quotes around it?

I have several expressions like:
glm(V12 ~ V3, family=binomial, data=df1)
glm(V12 ~ V4, family=binomial, data=df1)
...
glm(V12 ~ V8, family=binomial, data=df1)

As you can see, the only differences among them are V3 ... V8.
Because sometimes several of these expressions are performed many times,
I want to use a variable "i" to change the V3 ... V8. I did this with:

 > i <- 3:8
 > glm(V12 ~ paste("V", i, sep=""), family=binomial,
data=df1)

However, it seems the paste always returns a variable name with a pair 
of quotes, which were wrong in such condition.
I only find a function "sQuote" to add quotes to a string, and it
looks
I am looking for an opposite function of it.
Any advice will be appreciated.

Hi, Jing Jiang,

maybe

as.formula( paste( "V12 ~ V", i, sep = ""))

inside the call to glm() does what you need.

Hth  --  Gerrit


On Tue, 19 Apr 2011, JingJiang Yan wrote:
> Is there a function to get a string without a pair of quotes around it?
>
> I have several expressions like:
> glm(V12 ~ V3, family=binomial, data=df1)
> glm(V12 ~ V4, family=binomial, data=df1)
> ...
> glm(V12 ~ V8, family=binomial, data=df1)
>
> As you can see, the only differences among them are V3 ... V8.
> Because sometimes several of these expressions are performed many times,
> I want to use a variable "i" to change the V3 ... V8. I did this
with:
>
>> i <- 3:8
>> glm(V12 ~ paste("V", i, sep=""), family=binomial,
data=df1)
>
> However, it seems the paste always returns a variable name with a pair of 
> quotes, which were wrong in such condition.
> I only find a function "sQuote" to add quotes to a string, and it
looks I am
> looking for an opposite function of it.
> Any advice will be appreciated.
>
> ______________________________________________
> R-help at r-project.org 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.
>
---------------------------------------------------------------------
Dr. Gerrit Eichner                   Mathematical Institute, Room 212
gerrit.eichner at math.uni-giessen.de   Justus-Liebig-University Giessen
Tel: +49-(0)641-99-32104          Arndtstr. 2, 35392 Giessen, Germany
Fax: +49-(0)641-99-32109        http://www.uni-giessen.de/cms/eichner

This should be a FAQ: you are confusing the value with its printed 
representation.  Try

print(paste("V", 3:8, sep=""), quote=FALSE)

to see that there are no quotes, and you may want to read up on 
help("as.formula", package="stats") which has the examples
you are
searching for.

Allan

On 18/04/11 17:38, JingJiang Yan wrote:
> Is there a function to get a string without a pair of quotes around it?
>
> I have several expressions like:
> glm(V12 ~ V3, family=binomial, data=df1)
> glm(V12 ~ V4, family=binomial, data=df1)
> ...
> glm(V12 ~ V8, family=binomial, data=df1)
>
> As you can see, the only differences among them are V3 ... V8.
> Because sometimes several of these expressions are performed many times,
> I want to use a variable "i" to change the V3 ... V8. I did this
with:
>
> > i <- 3:8
> > glm(V12 ~ paste("V", i, sep=""), family=binomial,
data=df1)
>
> However, it seems the paste always returns a variable name with a pair 
> of quotes, which were wrong in such condition.
> I only find a function "sQuote" to add quotes to a string, and it
> looks I am looking for an opposite function of it.
> Any advice will be appreciated.
>
> ______________________________________________
> R-help at r-project.org 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.