[R] c(), rbind and cbind functions - why type of resulting object is double

[William Dunlap]

> I was wondering
> why I don't get an integer vector or and integer matrix with the following
> code:
> > z <- c(1, 2:0, 3, 4:8)
> > typeof(z)
> [1] "double"

It is because the literals 1 and 3 have type "double".  Append "L" to make
them literal integers.
  > typeof(c(1L, 2:0, 3L, 4:8))
  [1] "integer"
The colon function (":") returns an integer vector if it can do so without giving
a numerically incorrect answer.

  > typeof(1.0:3.0)
  [1] "integer"
  > typeof(1.5:3.5)
  [1] "double"

Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf
> Of Lourdes Peña Castillo
> Sent: Tuesday, January 22, 2013 9:26 AM
> To: r-help at r-project.org
> Subject: [R] c(), rbind and cbind functions - why type of resulting object is double
> 
> Hello Everyone,
> 
> I am using R 2.15.0 and I came across this behaviour and I was wondering
> why I don't get an integer vector or and integer matrix with the following
> code:
> 
> > z <- c(1, 2:0, 3, 4:8)
> 
> > typeof(z)
> 
> [1] "double"
> 
> > z <- rbind(1, 2:0, 3, 4:8)
> 
> Warning message:
> 
> In rbind(1, 2:0, 3, 4:8) :
> 
>   number of columns of result is not a multiple of vector length (arg 2)
> 
> > typeof(z)
> 
> [1] "double"
> 
> > z <- matrix(c(1, 2:0, 3, 4:8), nrow = 5)
> 
> > typeof(z)
> 
> [1] "double"
> 
> 
> Shouldn't be typeof integer? According to the online help if everything is
> integer the output should be integer.
> But if I do this, I get an integer matrix.
> 
> > z <- matrix(1:20, nrow = 5)
> 
> > typeof(z)
> 
> [1] "integer"
> 
> Thanks!
> 
> Lourdes
> 
> 	[[alternative HTML version deleted]]
> 
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