Booker, Andrew J wrote:
This is probably a know problem (problem for me anyway) in R but I
don't quite know what to search for in help archives. When I name a
column "x11" in a data frame R thinks a column named "x1" exists.
Not exactly. R uses partial matching here. Iff "x11" and "x1" exists, "x11" will be selected. Pretty much like matching for arguments in functions.
Probably you are looking for names(temd)?
Uwe Ligges
> In
my application I am trying to test for the existence of a column, then add it if it's not there. Here is a simple example:
temd <- data.frame(x11=c(0:10)) is.null(temd[["x1"]])
[1] FALSE
temd[["x1"]]
[1] 0 1 2 3 4 5 6 7 8 9 10
temd$x1
[1] 0 1 2 3 4 5 6 7 8 9 10
temd[,"x1"]
Error in "[.data.frame"(temd, , "x1") : undefined columns selected
This is in R 2.0.0.
Anyone know how to run (safely) through a list of names like "x1"-"x100" and check for data frame columns with the names?
----------------------------------------------------------- * Opinions herein are mine only *
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Andrew Booker The Boeing Company P.O. Box 3707 MC 7L-22 Seattle, WA 98124-2207 425-865-3573 FAX# 425-865-2966 [EMAIL PROTECTED]
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