Re: [Rd] access an element with empty name

[Serguei Sokol]

Le 14/05/2018 à 15:55, Kurt Hornik a écrit :

Serguei Sokol writes:

Hi,
I came across a case where I cannot access a list element by its empty name.
Minimal example can be constructed as
      x=list("A", 1)
      names(x)=c("a", "")
      x[["a"]]
      #[1]  "A"
      x[[""]]
      #NULL
      x$`a`
      #[1]  "A"
      x$``
      # Error: attempt to use zero-length variable name
      # but we can still access the second element by its index
      x[[2]]
      #[1] 1
To my mind, it should be perfectly legal to access an element by an
empty name as we can have for example
      match("", names(x))
      #[1] 2
Hence a traditional question: is it a bug or feature?

A feature according to the docs: ? Extract says

     Neither empty (‘""’) nor ‘NA’ indices match any names, not even
     empty nor missing names.

Thanks Kurt, I missed that one.

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