[R] Help with data.frame subsets
David Thibault
dthibault at esperion.com
Tue Mar 25 22:01:24 CET 2003
Hello all,
I'm trying to get a subset of a data frame by taking all rows where the 2nd
column is >= Min and <= Max. I can do that by a 2 step process similar to
the following:
subData <- dataFrame[dataFrame[,2] >= Min,]
subData2 <- subData[subData[,2] <= Max,]
Then I try to graph the results where col 2 is the X var and col 3 is the Y
var. Therefore I do the following:
X <- subData2[,2]
Y <- subData2[,3]
HOWEVER, sometimes subData2 is only left with 1 row remaining after the
subsetting operation. If it gets down to that point R seems to return the
results as a LIST and not as a data frame. Then when I do the X and Y
assignments above it gives the following error:
Error in subData2[, 2] : incorrect number of dimensions
I can't always assume that subData2 will be a list because most of the time
multiple rows are left in the subset and therefore it's still a data frame.
Does anyone have a solution for handling this kind of operation that won't
crash on me half the time?
Thanks in advance,
Dave
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