[R] Unexpected result for df column $ subset with non-existent name

[Andrew Simmons]

partial match attr is for something like

attr(data.frame(), "cla")

which will partially match to "class".

On Sun, Oct 30, 2022, 12:55 Joshua Ulrich <josh.m.ulrich using gmail.com> wrote:

> For what it's worth, I set these options to warn me about partial matches:
>
> options(warnPartialMatchArgs = TRUE,
>         warnPartialMatchAttr = TRUE,
>         warnPartialMatchDollar = TRUE)
>
> That warns about this particular case, as well as partial argument
> name matches in function calls. I don't remember what the partial
> match attr does, but past me wanted to be warned about it for some
> reason.
>
> Best,
> Josh
>
> On Fri, Oct 28, 2022 at 9:26 AM Bert Gunter <bgunter.4567 using gmail.com>
> wrote:
> >
> > Does this explain it: (from ?Extract)
> >
> >
> > name
> > A literal character string or a name (possibly backtick quoted). For
> > extraction, this is normally (see under ‘Environments’) **partially
> > matched** to the names of the object.
> >
> > -- Bert
> >
> > On Fri, Oct 28, 2022 at 6:53 AM Sergei Ko <sggp.sergei using gmail.com> wrote:
> > >
> > > Hi All,
> > >
> > > Just noticed that R returns results for non-existent name if you have
> > > another variable with the same beginning when you subset with $.
> > > See the code below:
> > > name_0 <- "ID"
> > > name_1 <- "name"
> > > name_2 <- "name1"
> > >
> > > v0 <- 1:200
> > > v1 <- c(rep(0,100), rep(1,100))
> > > v2 <- c(rep(0,50), rep(1,150))
> > >
> > > df <- as.data.frame(cbind(v0, v1, v2))
> > > colnames(df) <- c(name_0, name_1, name_2)
> > >
> > > df_1 <- df[, c(name_0, name_1)]
> > > df_2 <- df[, c(name_0, name_2)]
> > >
> > > table(df$name)
> > > table(df_1$name)
> > > table(df_2$name)
> > > colnames(df_2)[2] <- "name10"
> > > table(df_2$name)
> > > colnames(df_2)[2] <- "name_any"
> > > table(df_2$name)
> > > table(df_2[,"name"])
> > >
> > > The last row produces an error as intended.
> > > Any ideas?
> > >
> > > Win 10
> > > R version 4.2.1 (2022-06-23 ucrt) -- "Funny-Looking Kid"
> > >
> > > Regards,
> > > Sergiy
> > >
> > >         [[alternative HTML version deleted]]
> > >
> > > ______________________________________________
> > > R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
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> > > PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> > > and provide commented, minimal, self-contained, reproducible code.
> >
> > ______________________________________________
> > R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> > 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.
>
>
>
> --
> Joshua Ulrich  |  about.me/joshuaulrich
> FOSS Trading  |  www.fosstrading.com
>
> ______________________________________________
> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
>

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