Re: [R] Rule for accessing attributes?

From: Christos Hatzis <christos_at_nuverabio.com>
Date: Thu, 27 Mar 2008 00:35:59 -0400

You need to use the '@' operator to directly access attributes (not elements) of objects:

> lst_at_names

[1] "x" "y" "z"

See ?'@' for more details.

-Christos

> -----Original Message-----
> From: r-help-bounces_at_r-project.org
> [mailto:r-help-bounces_at_r-project.org] On Behalf Of Tribo Laboy
> Sent: Thursday, March 27, 2008 12:16 AM
> To: r-help_at_r-project.org
> Subject: [R] Rule for accessing attributes?
>
> Hi !
>
> I am a new user and quite confused by R-indexing.
>
> Make a list and get the attributes
> lst <- list(x = 1:3, y = 4:6, z = 7:9)
> attributes(lst)
>
> This returns:
>
> $names
> [1] "x" "y" "z"
>
> I can easily do:
>
> nm <-names(lst)
>
> or
>
> nm <-attr(lst,"names")
>
> which both return the assigned names of the named list 'lst',
> but why then this doesn't work:
>
> lst$names
>
> ?
>
> I am confused ... Moreover, I noticed that some of the objects (e.g.
> plot objects returned by ggplot) also have attributes when
> queried by the 'attributes' function, but they are accessible
> by the $ notation.
> (e.g.
>
> xydf <- data.frame(x = 1:5, y = 11:15)
> plt <- ggplot(data = xydf, aes(x = x,y = y)) + geom_point()
> attributes(plt)
>
> Now we can change the title:
>
> plt$title <- "My Title"
> plt
>
> So is it some inconsistency or am I missing something important?
>
> ______________________________________________
> R-help_at_r-project.org mailing list
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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.
>
>



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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. Received on Thu 27 Mar 2008 - 04:35:29 GMT

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