[R] match and incomparables

[McGehee, Robert]

Hello,
I was playing around with the newly implemented 'incomparables' argument
in 'match' and realized the argument does not behave anything like I
expected. Can someone explain what is going on here? Sorry if I'm
misreading the documentation.

> match(1:3, 1:3, incomparables=1)
[1] NA  2  3  # This seems right, the 1 in 'x' is 'incomparable'

> match(1:3, 1:3, incomparables=2)
[1] 1  2  3   # Shouldn't this be 1 NA 3? Why isn't the 2 incomparable?

> match(1:3, 1:3, incomparables=5)
[1] NA  2  3   # Why isn't the 5 ignored?

Note from ?match:
"incomparables: a vector of values that cannot be matched. Any value in
x matching a value in this vector is assigned the nomatch value. For
historical reasons, FALSE is equivalent to NULL."

Thanks in advance!
Robert

platform       i386-pc-mingw32             
arch           i386                        
os             mingw32                     
system         i386, mingw32               
status                                     
major          2                           
minor          7.2                         
year           2008                        
month          08                          
day            25                          
svn rev        46428                       
language       R                           
version.string R version 2.7.2 (2008-08-25)

Robert McGehee, CFA
Geode Capital Management, LLC
One Post Office Square, 28th Floor | Boston, MA | 02109
Tel: 617/392-8396    Fax:617/476-6389
mailto:robert.mcgehee at geodecapital.com



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