using ``<-'' in function argument
On 12/02/2010 09:35 PM, Jinsong Zhao wrote:
Hi there, In function, it's usually using ``='' to assign default value for function argument. For newbie, it's possible to using ``<- '' to assign value for function argument. Although it's not a correct way, R don't give any warning message.
> matrix(1:20, ncol <- 4)
[,1] [,2] [,3] [,4] [,5] [1,] 1 5 9 13 17 [2,] 2 6 10 14 18 [3,] 3 7 11 15 19 [4,] 4 8 12 16 20 It seems that R ignore the ``ncol <-'' and assign the value 4 to ``nrow''. Would anyone here give a more detailed explanation about this? Thanks in advance!
Yes, R gives the global variable ncol a value of 4. Try typing > ncol before and after your example. The second argument to the matrix function is now the value 4, and R uses positional matching to give that argument (nrow) a value of 4. Thus, the result. Moral of the story: don't do that. :) --Erik
Best regards, Jinsong
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