[Rd] Argument recycling in substring()

[Hervé Pagès]

Hi,

According to its man page substring() "expands (its) arguments
cyclically to the length of the longest _provided_ none are of
zero length".

So, as expected, I get an error here:

   > substring("abcd", first=2L, last=integer(0))
   Error in substring("abcd", first = 2L, last = integer(0)) :
     invalid substring argument(s)

But I don't get one here:

   > substring(character(0), first=1:2, last=3L)
   character(0)

which is unexpected.

Otherwise, yes substring() will recycle its arguments to the
length of the longest:

   > substring("abcd", first=1:3, last=4:3)
   [1] "abcd" "bc"   "cd"

Cheers,
H.

-- 
Hervé Pagès

Program in Computational Biology
Division of Public Health Sciences
Fred Hutchinson Cancer Research Center
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