Hi Richard, 3D is automatically generated by the mailing list software, probably because I had ] followed by =3D without a space in the original post.
What I meant was to calculate x[i] =3D x[i-1] + y[i-1] For example, if X <- 1:10 Then I want the vector Y to be 1, 3, 6, 10, 15, 21, 28, 36, 45, 55, or in other words Y[i] =3D y[i-1] + x[i]. Yes, cumsum does the trick for this. This is what I need. Thanks. Just curious, do you know how to calculate the more generic x[i] <- f( x[i-1], y[i-1] )? Thanks, Geoffrey -----Original Message----- From: Richard M. Heiberger [mailto:[EMAIL PROTECTED] Sent: Tuesday, December 26, 2006 9:56 AM To: Geoffrey Zhu; r-help@stat.math.ethz.ch Subject: Re: [R] vectorizing an iterative process. > x[i]=3D3Dx[i-1]+y[i-1] for all i, how can I do this without a loop? It looks like x <- cumsum(y) What does 3D mean? _______________________________________________________=0A= =0A= =0A= The information in this email or in any file attached hereto is=0A= intended only for the personal and confidential use of the individual=0A= or entity to which it is addressed and may contain information that is=0A= proprietary and confidential. If you are not the intended recipient of=0A= this message you are hereby notified that any review, dissemination,=0A= distribution or copying of this message is strictly prohibited. This communi= cation is for information purposes only and should not be regarded as an off= er to sell or as a solicitation of an offer to buy any financial product. Em= ail transmission cannot be guaranteed to be secure or error-free. ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.