R help - Mar 2017 - change the value of vector based on the string of its name

Dear R-users,

Imagine I have 3 vectors:
*proc1<-0*
*proc2<-0*
*cpd<-c("proc1","proc2")*

How can I change the value of proc1 to 1, based on vector cpd only?
I tried with *as.factor(cpd[1])<-1*, but it produces an error.

Any idea how could I achieve that?

	[[alternative HTML version deleted]]

> On Mar 24, 2017, at 10:12 AM, Qill Bel <qillbel at gmail.com> wrote:
> 
> Dear R-users,
> 
> Imagine I have 3 vectors:
> *proc1<-0*
> *proc2<-0*
> *cpd<-c("proc1","proc2")*
The `cpd` vector has only character values in it, and has no relation to either
the `proc1` or `proc2` vectors. If you want it refer to  them (or contain their
values),  then omit the quotes. The values will not retain their names in this
instance. The R names `proc`` and `proc2` will be looked up and their values
places in an unnamed numeric vector. You could however make it so with:

cpd<-c("proc1"=proc1,"proc2"=proc2)

#The quotes are not needed and so this would be equivalent"

cpd<-c( proc1=proc1, proc2=proc2)

There is a `get`-function, but teaching you how to use it to solve the problem
is likely to be a disservice since it would allow you to continue using R as a
macro-processor.
> 
> How can I change the value of proc1 to 1, based on vector cpd only?
> I tried with *as.factor(cpd[1])<-1*, but it produces an error.
Doesn't make much sense to me to use assignment to a factor in this
instance, but that's probably because we come from different programming
backgrounds. Neither your code nor mine would have produced a factor vector. You
should say in natural language what it is that you want to happen.

(Perhaps) Try this:

cpd[1] <- 1

Or:

cpd['proc1'] <- 1

> 
> Any idea how could I achieve that?
> 
> 	[[alternative HTML version deleted]]
And learn to post in plain text. Reading the Posting Guide will also be a good
idea. As would be studying a bit longer the "Introduction to R" that
is shipped with every installation.

> 
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
David Winsemius
Alameda, CA, USA

Hi Qill,
If I have interpreted your example correctly:

proc1<-0
proc2<-0
cpd<-c("proc1","proc2")
assign("proc1",which(cpd=="proc1"))

Jim


On Sat, Mar 25, 2017 at 4:12 AM, Qill Bel <qillbel at gmail.com>
wrote:
> Dear R-users,
>
> Imagine I have 3 vectors:
> *proc1<-0*
> *proc2<-0*
> *cpd<-c("proc1","proc2")*
>
> How can I change the value of proc1 to 1, based on vector cpd only?
> I tried with *as.factor(cpd[1])<-1*, but it produces an error.
>
> Any idea how could I achieve that?
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.