[R] [FORGED] Re: identical() versus sapply()
apa at stowers.org
Mon Apr 11 18:30:29 CEST 2016
Ok, I see the difference between 1 and 1:2, I'll just leave it as one of those "only in R" things.
But it seems then, that as.numeric() should guarantee a FALSE outcome, yet it does not.
To build on what Rolf pointed out, I would really love for someone to explain this one:
int [1:2] 1 2
num [1:2] 1 2
int [1:2] 1 2
Which doubly makes no sense. 1) Either the class is "numeric" or it isn't; I did not call as.integer() here. 2) method of recasting should not affect final class.
From: Rolf Turner [mailto:r.turner at auckland.ac.nz]
Sent: Saturday, April 09, 2016 5:27 AM
To: Jeff Newmiller
Cc: Paulson, Ariel; 'r-help at r-project.org'
Subject: Re: [FORGED] Re: [R] identical() versus sapply()
On 09/04/16 16:24, Jeff Newmiller wrote:
> I highly recommend making friends with the str function. Try
> str( 1 )
> str( 1:2 )
Interesting. But to me counter-intuitive. Since R makes no distinction between scalars and vectors of length 1 (or more accurately I think, since in R there is *no such thing as a scalar*, only a vector of length
1) I don't see why "1" should be treated in a manner that is categorically different from the way in which "1:2" is treated.
Can you, or someone else with deep insight into R and its rationale, explain the basis for this difference in treatment?
> for the clue you need, and then
> sapply( 1:2, identical, 1L )
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