Your expectations of the | operator don't seem fair... you should reread ?"|" and perhaps the "Introduction to R" document.

In particular, there is no "between" operator in R. The %in% operator allows you an efficient way to identify any of many specific cases. If you are working with ordered factors then you can perform < and > comparisons, but that can affect the statistical algorithms you apply elsewhere.
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B Jessop <deelman@hotmail.com> wrote:



Dear r-help,



I would like to select a subset of levels from a factor variable in a data frame and return a data frame.



The data set consists of 3 variables, 2 of which are factors (Site, Fish) and one numeric (Datavalue) as follows:



Site Fish Datavalue

AB 2-1 2.3 

AB 2-1 2.4 

AB 2-1 2.2 

AB 2-2 2.6 

AB 2-2 2.5 

AB 2-2 2.7 

AB 2-3 1.6 

AB 2-3 1.5 

AB 2-3 1.4 

etc

AB 2-20 3.1 

AB 2-20 2.9 

AB 2-20 3.0 



I would like to create a subset containing all variable rows but for only, say, Fish 2-1, 2-2, and 2-3. The following code:



Df2 <- subset(Df1, Eel=="2-1" | Eel=="2-3") selects only Eel 2-1 and 2-3. The use of a ":" rather than "|" gives an error message. My other approaches did not work. Any 



suggestions for doing this task would be much appreciated.



Regards,

BJ 
		 	 		 
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