[Rd] unlist strips date class

2016-12-02 Thread Kenny Bell 
Is this a bug?

> unlist(list(as.Date("2015-01-01")))
[1] 16436

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Re: [Rd] unlist strips date class

2016-12-02 Thread Dirk Eddelbuettel 

On 2 December 2016 at 10:45, Kenny Bell wrote:
| Is this a bug?
| 
| > unlist(list(as.Date("2015-01-01")))
| [1] 16436

Not really, it is documented.

S3 classes operate via an attribute tag, and attributes get dropped by
certain base functions. I must have hit something like the following about a
thousand times by now:

R> for (i in as.Date("2015-01-01")+ 0:2) print(i)
[1] 16436
[1] 16437
[1] 16438
R>

Live and learn.

Dirk

-- 
http://dirk.eddelbuettel.com | @eddelbuettel | e...@debian.org

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[Rd] Spam messages

2016-12-02 Thread Kenny Bell 
Have others received spam messages after posting to this list?

The two problem emails are hodgesdonna...@yahoo.com and
amykristen4...@octbm.com.

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Re: [Rd] unlist strips date class

2016-12-02 Thread Hervé Pagès 

Hi,

On 12/02/2016 10:45 AM, Kenny Bell wrote:

Is this a bug?


unlist(list(as.Date("2015-01-01")))

[1] 16436


Good question.

More generally one might reasonably expect 'unlist(x)' to be equivalent
to 'do.call(c, x)' on a list 'x' where all the list elements are atomic
vectors:

  x <- list(1:3, letters[1:2])
  unlist(x)
  # [1] "1" "2" "3" "a" "b"
  do.call(c, x)
  # [1] "1" "2" "3" "a" "b"

However, if the list contains dates:

  x <- list(as.Date("2015-01-01") + 0:2, as.Date("2016-12-02"))
  unlist(x)
  # [1] 16436 16437 16438 17137
  do.call(c, x)
  # [1] "2015-01-01" "2015-01-02" "2015-01-03" "2016-12-02"

then 'unlist(x)' drops the attributes and 'do.call(c, x)' does not.

And if the list contains factors:

  x <- list(factor("Z"), factor(c("a", "Z", "b")))
  unlist(x)
  # [1] Z a Z b
  # Levels: Z a b
  do.call(c, x)
  # [1] 1 1 3 2

then it's the other way around. Also note that the fact that the first
2 numbers in the result of 'do.call(c, x)' are the same is
confusing/misleading. Hard to see how this result could be useful
to anybody.

These inconsistencies might well be documented but hopefully they can
be addressed.

Cheers,
H.

--
Hervé Pagès

Program in Computational Biology
Division of Public Health Sciences
Fred Hutchinson Cancer Research Center
1100 Fairview Ave. N, M1-B514
P.O. Box 19024
Seattle, WA 98109-1024

E-mail: hpa...@fredhutch.org
Phone:  (206) 667-5791
Fax:(206) 667-1319

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