[R] problem with for()

Marc Schwartz MSchwartz at mn.rr.com
Wed Aug 3 23:37:30 CEST 2005


On Wed, 2005-08-03 at 23:24 +0200, Simone Gabbriellini wrote:
> Dear list,
> can someone tell me why this two pieces of code give me the same  
> results?
> 
>  > for(i in 0:5){ sum[i] = i }
>  > sum
> [1] 1 2 3 4 5
> 
>  > for(i in 1:5){ sum[i] = i }
>  > sum
> [1] 1 2 3 4 5
> 
> shouldn't the first one be
> 
> 0 1 2 3 4 5
> 
> thank you,
> simone

No....the indexing of R objects is 1 based. Thus your first loop tried
to set i[0], which is a non-existent entry.

> i <- 0:5

> i
[1] 0 1 2 3 4 5

> i[0]
numeric(0)

> i[1]
[1] 0

HTH,

Marc Schwartz




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