yea, I have read the help. But some one tell me that i f you want use a vector that you don't know it's length, you should use xx=numric(0) , is it not right? If it isn't right, how can I do? thanks -----Original Message----- From: Douglas Grove [mailto:dgrove at fhcrc.org] Sent: Wednesday, June 01, 2005 6:27 AM To: luan_sheng Subject: Re: [R] FW: why is it numeric(0)? Have you read the help page for numeric (?numeric) to understand what it does? You should really look at help pages prior to posting. numeric(x) returns a numeric vector of length x, with all entries initialized to zero so numeric(1) returns 0, numeric(2) returns c(0,0) etc. numeric(0) returns a numeric vector of *length 0*, so when you add anything to it you get the same result (it's basically a numeric NULL)
On Wed, 1 Jun 2005, luan_sheng wrote:
hello,everyone. I have one question: example 1
x=numeric(0) y=5 print(x+y)
numeric(0) example 2
x=numeric(1) y=5 print(x+y)
[1] 5 why the print(x+y) is numeric(0) at the first example, but the result is 0 at the second example?
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