[Rd] inconsistency in treatment of USE.NAMES argument

Hervé Pagès hpages at fredhutch.org
Mon Feb 8 19:48:50 CET 2016


Both vapply() and sapply() support the 'USE.NAMES' argument. According
to the man page:

   USE.NAMES: logical; if ‘TRUE’ and if ‘X’ is character, use ‘X’ as
             ‘names’ for the result unless it had names already.

But if 'X' has names already and 'USE.NAMES' is FALSE, it's not clear
what will happen to the names. Are they going to propagate to the
result or not? Unfortunately, vapply() and sapply() give a different

   > vapply(list(A="a", B=1:2), is.integer, logical(1), USE.NAMES=FALSE)
   [1] FALSE  TRUE

   > sapply(list(A="a", B=1:2), is.integer, USE.NAMES=FALSE)
       A     B

Wouldn't it make sense to have vapply() and sapply() treat the
'USE.NAMES' argument consistently? The behavior of vapply() seems
to make more sense to me. Note that it's consistent with what mapply()

   > mapply(is.integer, list(A="a", B=1:2), USE.NAMES=FALSE)
   [1] FALSE  TRUE

If the behavior of sapply() cannot be changed, at least the man page
could clarify what happens when 'USE.NAMES' is FALSE, which is
different for each function.


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: hpages at fredhutch.org
Phone:  (206) 667-5791
Fax:    (206) 667-1319

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