[R] subset using noncontiguous variables by name (not index)
Muenchen, Robert A (Bob)
muenchen at utk.edu
Sun Aug 26 22:37:53 CEST 2007
I'm using the subset function to select a list of variables, some of
which are contiguous in the data frame, and others of which are not. It
works fine when I use the form:
In reality, my list is far more complex. So I would like to store it in
a variable to substitute in for c(x1,x3:x5,x7) but cannot get it to
work. That use of the c function seems to violate R rules, so I'm not
sure how it works at all. A small simulation of the problem is below.
If the variable names & orders were really this simple, I could use
summary( mydata[ ,c(1,3:5,7) ] )
but alas, they are not.
How does the c function work this way in the first place, and how can I
make this substitution?
mydata <- data.frame(
# This does what I want.
# Can I substitute myVars?
myVars1 <- c(x1,x3:x5,x7)
# Not looking good!
# This doesn't do the right thing.
# Total desperation on this attempt:
myVars2 <- "x1,x3:x5,x7"
# This doesn't work either.
Bob Muenchen (pronounced Min'-chen), Manager
Statistical Consulting Center
U of TN Office of Information Technology
200 Stokely Management Center, Knoxville, TN 37996-0520
Voice: (865) 974-5230
FAX: (865) 974-4810
Email: muenchen at utk.edu
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