R help - Aug 2011 - How to use 'switch' with strings containing spaces?

Hi,

Does anyone know if the alternatives in the 'switch' function can be
specified as strings containing spaces?  Neither of the two approaches below
works.


switch(expr, "Choice 1"="My first choice", "Choice
2"="My 2nd choice", "Choice 3"="My 3rd
choice")


x <- c("Choice 1", "Choice 2", "Choice 3")
switch(expr, x[1]="My first choice", x[2]="My 2nd choice",
x[3]="My 3rd choice")


If the intended functionality can be achieved by a different function(s),
I'd most appreciate such a suggestion as well.

Many thanks,
Mauricio

	[[alternative HTML version deleted]]

On Aug 16, 2011, at 4:53 PM, Mauricio Cornejo wrote:
> Hi,
>
> Does anyone know if the alternatives in the 'switch' function can
be
> specified as strings containing spaces?  Neither of the two  
> approaches below works.
>
>
> switch(expr, "Choice 1"="My first choice", "Choice
2"="My 2nd
> choice", "Choice 3"="My 3rd choice")
>
>
> x <- c("Choice 1", "Choice 2", "Choice 3")
> switch(expr, x[1]="My first choice", x[2]="My 2nd
choice", x[3]="My
> 3rd choice")
>
>
> If the intended functionality
Right... and what might that be... in a natural language if you  
please. Deducing intention from failed efforts in a computer language  
are a request for mind-reading.

(Puts envelope to forehead. The answer is probably ....  ?match )

switch() is designed to dispatch to a function call. match() is  
designed to return an item from a vector.
> can be achieved by a different function(s), I'd most appreciate such  
> a suggestion as well.
>
 > x <- c("Choice 1", "Choice 2", "Choice
3")
 > x <- c("Choice 1", "Choice 2", "Choice
3")
 > match("Choice 2", x)
{1] 2   # returns a vector easily used as index to another vector

 > c("My first choice", "My 2nd choice","My 3rd
choice")
[ match("Choice 2", x)]
[1] "My 2nd choice"


David Winsemius, MD
West Hartford, CT

The problem is that your argument expr is undefined.

This works
> switch("Choice 2", "Choice 1"="My first
choice", "Choice 2"="My 2nd
choice", "Choice 3"="My 3rd choice")
[1] "My 2nd choice"
> x <- "Choice 2"
> switch(x, "Choice 1"="My first choice", "Choice
2"="My 2nd choice",
"Choice 3"="My 3rd choice")
[1] "My 2nd choice"
>



On Tue, Aug 16, 2011 at 4:53 PM, Mauricio Cornejo
<mauriciocornejo@yahoo.com
> wrote:
> Hi,
>
> Does anyone know if the alternatives in the 'switch' function can
be
> specified as strings containing spaces?  Neither of the two approaches
below
> works.
>
>
> switch(expr, "Choice 1"="My first choice", "Choice
2"="My 2nd choice",
> "Choice 3"="My 3rd choice")
>
>
> x <- c("Choice 1", "Choice 2", "Choice 3")
> switch(expr, x[1]="My first choice", x[2]="My 2nd
choice", x[3]="My 3rd
> choice")
>
>
> If the intended functionality can be achieved by a different function(s),
> I'd most appreciate such a suggestion as well.
>
> Many thanks,
> Mauricio
>
>        [[alternative HTML version deleted]]
>
>
> ______________________________________________
> R-help@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<http://www.r-project.org/posting-guide.html>
> and provide commented, minimal, self-contained, reproducible code.
>
>
	[[alternative HTML version deleted]]