'+' is a generic function, so different methods can be defined
for different classes of objects. Consider the following:
methods('+')
[1] +.Date +.POSIXt # Methods defined for 'Date' and 'POSIXt' objects
> args('+.Date') # standard argument names are e1 and e2
function (e1, e2)
NULL
> '+.x' <- function(e1, e2)e1*e2 # Define '+' for an object of class 'x'
> methods('+')
[1] +.Date +.POSIXt +.x # Confirm: "+.x" defined.
> xx <- 3
> class(xx) <- 'x' # Create an object of class 'x'
> xx+2 # 3+2=6, right?
[1] 6
attr(,"class")
[1] "x"
>
Enjoy.
Spencer
On 3/30/2011 1:31 PM, baptiste auguie wrote:
Hi,
Also, try this and rm() it immediately,
`+`<- function(x, y) x - y
1+1
rm(`+`)
1+1
baptiste
On 31 March 2011 05:04, Chuanlong Du<dcl...@iastate.edu> wrote:
Hello, everyone!
Does anyone know how make some symbols have special means in R? For example,
we know that "+" in R means the sum of the two operand on its left and
right. I want to define some operators in R by myself. Is this possible?
Regards!
--
Chuanlong Du
Department of Statistcis
Iowa State University
Ames, IA, US 50011
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Spencer Graves, PE, PhD
President and Chief Operating Officer
Structure Inspection and Monitoring, Inc.
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