Thanks Sarah. I have read about the problems with attach(), and I will try to avoid it. I have now found the line that's causing the problem is:
>setwd("z:/homework") With that line in place, either in a program or in Rprofile.site (?), then the moment I run R and simply enter (before reading any data) summary(mydata) I get sample statistics for a dozen variables! Do not save the workspace? I thought the option to save/use a binary file is meant to be convenient. I like working in the same working directory, and I like .rdata files. Does this sound hopeless? Thanks. At 09:26 PM 11/15/2011, Sarah Goslee wrote: >Hi, > >The obvious answer is don't use attach() and you'll never have >that problem. And see further comments inline. > >On Tue, Nov 15, 2011 at 6:05 PM, Steven Yen <s...@utk.edu> wrote: > > Can someone help me with this variable/data reading issue? > > I read a csv file and transform/create an additional variable (called y). > > > > The first set of commands below produced different sample statistics > > for hw11$y and y > > > > In the second set of command I renameuse the variable name yy, and > > sample statistics for $hw11$yy and yy are identical. > > > > Using y <- yy fixed it, but I am not sure why I would need to do that. > > > > That "y" appeared to have come from a variable called "y" from > > another data frame (unrelated to the current run). > > > > Help! > > > > > setwd("z:/homework") > > > sink ("z:/homework/hw11.our", append=T, split=T) > > > hw11 <- read.csv("ij10b.csv",header=T) > > > hw11$y <- hw11$e3 > > > attach(hw11) > > The following object(s) are masked _by_ '.GlobalEnv': > > y > >Look there. R even *told* you that it was going to use the >y in the global environment rather than the one you were >trying to attach. > >The other solution: don't save your workspace. Your other >email on this topic suggested to me that there is a .RData >file in your preferred working directory that contains an >object y, and that's what is interfering with what you think >should happen. > >Deleting that file, or using a different directory, or removing >y before you attach the data frame would all work. > >But truly, the best possible strategy is to avoid using attach() >so you don't have to worry about which object named y is >really being used because you specify it explicitly. > > > > > (n <- dim(hw11)[1]) > > [1] 13765 > > > summary(hw11$y) > > Min. 1st Qu. Median Mean 3rd Qu. Max. > > 0.0000 0.4500 1.0000 1.6726 2.0000 140.0000 > > > length(hw11$y) > > [1] 13765 > > > summary(y) > > Min. 1st Qu. Median Mean 3rd Qu. Max. > > 0.00000 0.00000 0.00000 0.24958 0.00000 1.00000 > > > length(y) > > [1] 601 > > > > > > > > setwd("z:/homework") > > > sink ("z:/homework/hw11.our", append=T, split=T) > > > hw11 <- read.csv("ij10b.csv",header=T) > > > hw11$yy <- hw11$e3 > > > attach(hw11) > > > hw11$yy <- hw11$e3 > > > summary(hw11$yy) > > Min. 1st Qu. Median Mean 3rd Qu. Max. > > 0.0000 0.4500 1.0000 1.6726 2.0000 140.0000 > > > length(hw11$yy) > > [1] 13765 > > > summary(yy) > > Min. 1st Qu. Median Mean 3rd Qu. Max. > > 0.0000 0.4500 1.0000 1.6726 2.0000 140.0000 > > > length(yy) > > [1] 13765 > > > > > > >-- >Sarah Goslee >http://www.functionaldiversity.org -- Steven T. Yen, Professor of Agricultural Economics The University of Tennessee http://web.utk.edu/~syen/ [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.