[R] How to switch off accepting the shortcut of column names
Prof Brian Ripley
ripley at stats.ox.ac.uk
Tue Oct 30 16:34:36 CET 2007
If you had updated your R before posting (as the posting guide suggested)
you would have found such an option under ?options. It was new in R
On Tue, 30 Oct 2007, P. Olsson wrote:
> Dear R-users,
> currently I am working with the R version 2.4.1.
> I realized it has a feature, which might be wonderful (as so many things in
> R), but in this case might be a bit dangerous as well. It seems that columns
> of a data frame can be called just by indicating the first letter of the
> name of the column.
Well, this applies to lists not just data frame, and to partial matching
not just the first letter.
If you want only exact matches I suggest you use other operators, e.g.
dat[["f"]] will warn in 2.6.x and fail in R-devel.
> For example:
> first_item <- seq(1,10)
> second_item <- seq(11,20)
> dat <- data.frame(first_item, second_item)
> #  "first_item" "second_item"
> #  1 2 3 4 5 6 7 8 9 10
> #  11 12 13 14 15 16 17 18 19 20
> The good thing is, that if there is more than one column starting with the
> same letter(s), more than one letter has to be given to call the column.
> However, I would appreciate if I could choose an option in my workspace,
> whether this type of shortcut is allowed or not.
> Is there such an option?
> Thanks for any potential hints.
> Best wishes,
> P. Olsson
> [[alternative HTML version deleted]]
> R-help at r-project.org mailing list
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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