[R] Is k equivalent to k:k ?

Liaw, Andy andy_liaw at merck.com
Mon Aug 2 17:08:30 CEST 2004


See ?":", especially the `Value' section.  Numeric literals in R is double
by default.

Andy

> From: Georgi Boshnakov
> 
> Hi,
> 
> I wonder if the following (apparent) inconsistency is a bug 
> or feature. 
> Since scalars are simply vectors of length one I would think that 
>       a      and 
>       a:a 
> produce the same result. For example,
> 
> > identical(4.01,4.01:4.01)
> [1] TRUE
> 
> However,
> 
> identical(4,4:4)
> [1] FALSE
> 
> and
> 
> > identical(4.0,4.0:4.0)
> [1] FALSE
> 
> A closer look reveals that the colon operator produces 
> objects of different class, e.g.
> 
> > class(4)
> [1] "numeric"
> > class(4.0)
> [1] "numeric"
> 
> but
> 
> > class(4:4)
> [1] "integer"
> > class(4.0:4.0)
> [1] "integer"
> 
> 
> Georgi Boshnakov
> 
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> ----------------
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> Mathematics Department                           email: 
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