That's because S does partial matching of component names, if it can be done unambiguously:
> z <- list(aaa=1, bbb=2) > z$a [1] 1 > z[["a"]] [1] 1 > z["a"] $"NA" NULL > z["aaa"] $aaa [1] 1 Andy From: Hong Ooi > > Hi, > > I came across some rather unexpected behaviour the other day with > assigning names and lists. Here's an example. > > > z <- list(aaa=1, bbb=2) > > z > $aaa > [1] 1 > > $bbb > [1] 2 > > Note that z has members named "aaa" and "bbb". Now: > > > names(z$a) <- "X" > > z > $aaa > [1] 1 > > $bbb > [1] 2 > > $a > X > 1 > > I would have expected that trying to name z$a would either > give an error > (because z doesn't have an element "a") or would cause z$aaa to be > modified (due to partial name matching). I didn't expect that a new > list member would be created. > > I've checked that this is consistent across SPlus 2000, SPlus 7, and R > 2.2 for Windows. Can someone give an explanation for why this is > happening? > > > -- > Hong Ooi > Senior Research Analyst, IAG Limited > 388 George St, Sydney NSW 2000 > (02) 9292 1566 > > > ______________________________________________________________ > _________________________ > > The information transmitted in this message and its > attachments (if any) is intended > only for the person or entity to which it is addressed. > The message may contain confidential and/or privileged > material. Any review, > retransmission, dissemination or other use of, or taking of > any action in reliance > upon this information, by persons or entities other than the > intended recipient is > prohibited. > > If you have received this in error, please contact the sender > and delete this e-mail > and associated material from any computer. > > The intended recipient of this e-mail may only use, > reproduce, disclose or distribute > the information contained in this e-mail and any attached > files, with the permission > of the sender. > > This message has been scanned for viruses with Symantec Scan > Engine and cleared by > MailMarshal. > > ______________________________________________ > [email protected] mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html > > ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
