[R] problem with function "rep"

Marc Schwartz marc_schwartz at comcast.net
Thu Jun 12 17:09:31 CEST 2008

on 06/12/2008 09:48 AM Julien Hunt wrote:
> To whom it may concern,
> I am currently writing a program where I need to use function rep.
> The results I get are quite confusing. Given two 
> vectors A and B, I want to replicate a[1] b[1] 
> times, a[2] b[2] times and so on.
> All the entries of vector B are positive integers.
> My problem comes from the fact that if I sum up 
> all the elements of B, I get a certain 
> value  x(for example 10000). And if i calculate 
> the length of the vector obtained after 
> replication, I dont always get x(10000) but 
> sometimes I get x sometimes I get 9999 instead of 10000.
> Has this problem been reported before? Do you 
> need more information on my specific program.
> Thanks for your time and help,
> Best regards,
> Julien Hunt

An example would be most helpful, but presuming that you are using 
something along the lines of:

   rep(a, each = b)

I would check to be sure that:

   length(a) == length(b)

lest you end up with the issue of recycling values.


Marc Schwartz

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