[R] Filter out some levels?

[Chuck Cleland]

Christian Schulz wrote:
> how is it possible t cut some levels from one factor to  subsetting  a 
> data.frame on?
> 
> subdata <- subset(data, data$FACTOR="1" | 
> data$FACTOR="BETA" | data$FACTOR="XY")
> ???
> 
> Maybe a modifcation here is better, but how?
> mergex[mergex$PLZX %in% levels(mergex$PLZX) ,]

Christian:

You need element by element comparison.  Does this help?

mydata <- data.frame(FACTOR = c("1", "BETA", "XY", "DROP"), Y = 
runif(4))

mydata[mydata$FACTOR=="1" | mydata$FACTOR=="XY" | 
mydata$FACTOR=="BETA",]

   FACTOR         Y
1      1 0.5111390
2   BETA 0.7219460
3     XY 0.1346707

mydata[mydata$FACTOR!="DROP",]

   FACTOR         Y
1      1 0.5111390
2   BETA 0.7219460
3     XY 0.1346707

See ?"=="

-- 
Chuck Cleland, Ph.D.
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