R help - Mar 2011 - simple if question

Hi everyone,
I have just got different samples from a dataframe (independent and 
exclusive, there aren't common elements among them). I want to create a 
variable that indicate the sampling selection of the elements in the 
original dataframe (for example, 0 = no selected, 1= sample 1, 2=sample 
2, etc.).

I have tried to do it with ifelse command, but the problem is that the 
second line replaces the values of the first line, and I haven't been 
able to do it with the if command (I got this error: In if (data$school 
%in% sample1) { :
   the condition has length > 1 and only the first element will be used)

data$selection <- ifelse(data$school %in% sample1, 1, 0)
data$selection <- ifelse(data$school %in% sample2, 2, 0)

Any ideas?
Thank you in advance.

-- 
Sebasti?n Daza
sebastian.daza at gmail.com

On Mar 26, 2011, at 7:05 PM, Sebasti?n Daza wrote:
> Hi everyone,
> I have just got different samples from a dataframe (independent and  
> exclusive, there aren't common elements among them). I want to  
> create a variable that indicate the sampling selection of the  
> elements in the original dataframe (for example, 0 = no selected, 1=  
> sample 1, 2=sample 2, etc.).
>
> I have tried to do it with ifelse command, but the problem is that  
> the second line replaces the values of the first line, and I haven't  
> been able to do it with the if command (I got this error: In if (data 
> $school %in% sample1) { :
>  the condition has length > 1 and only the first element will be used)
>
Nested ifelse's should work. There may be a limit to nested depth.

data$selection <- ifelse(data$school %in% sample1, 1,   # else
                      ifelse(data$school %in% sample2, 2, #else
                                                       0) )
>
> Any ideas?
> Thank you in advance.
>
> -- 
> Sebasti?n Daza
> sebastian.daza at gmail.com
>
> ______________________________________________
> 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.
David Winsemius, MD
West Hartford, CT

Posting some sample data would help, but I think something like this
is what you want

data[data$school=='Cornell University',]

For example

CO2[CO2$Type=='Quebec',]

Tom

2011/3/26 Sebasti?n Daza <sebastian.daza at
gmail.com>:
> Hi everyone,
> I have just got different samples from a dataframe (independent and
> exclusive, there aren't common elements among them). I want to create a
> variable that indicate the sampling selection of the elements in the
> original dataframe (for example, 0 = no selected, 1= sample 1, 2=sample 2,
> etc.).
>
> I have tried to do it with ifelse command, but the problem is that the
> second line replaces the values of the first line, and I haven't been
able
> to do it with the if command (I got this error: In if (data$school %in%
> sample1) { :
> ?the condition has length > 1 and only the first element will be used)
>
> data$selection <- ifelse(data$school %in% sample1, 1, 0)
> data$selection <- ifelse(data$school %in% sample2, 2, 0)
>
> Any ideas?
> Thank you in advance.
>
> --
> Sebasti?n Daza
> sebastian.daza at gmail.com
>
> ______________________________________________
> 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.
>