[R] Add vectors of unequal length without recycling?

[PIKAL Petr]

Hi

If some feature does not suit your intentions you can make your own. Especially in this simple case.

myadd<-function(x,y) {

if(length(x)!=length(y)) {

n <- max(length(x), length(y))
length(x) <- n
length(y) <- n
x[is.na(x)]<-0
y[is.na(u)]<-0
}
x+y
}

> myadd(u,v)
[1] 11 22 33  4  5  6  7  8  9
>

But usually data to R are imported as data frames and missing values are set to NA.

In such case you could use rowSums with na.rm argument.

Cheers
Petr

> -----Original Message-----
> From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Maingo via R-
> help
> Sent: Wednesday, December 13, 2017 6:41 AM
> To: r-help at r-project.org
> Subject: [R] Add vectors of unequal length without recycling?
>
> I'm a newbie for R lang. And I recently came across the "Recycling Rule" when
> adding two vectors of unequal length.
>
> I learned from this tutor [ http://www.r-tutor.com/r-
> introduction/vector/vector-arithmetics ] that:
>
> """"""
>
> If two vectors are of unequal length, the shorter one will be recycled in order to
> match the longer vector. For example, the following vectors u and v have
> different lengths, and their sum is computed by recycling values of the shorter
> vector u.
>
> > u = c(10, 20, 30)
>
> > v = c(1, 2, 3, 4, 5, 6, 7, 8, 9)
>
> > u + v
>
> [1] 11 22 33 14 25 36 17 28 39
>
> """"""
>
> And I wondered, why the shorter vecter u should be recycled? Why not just
> leave the extra values(4,5,6,7,8,9) in the longer vector untouched by default?
>
> Otherwise is it better to have another function that could add vectors without
> recycling? Right now the recycling feature bugs me a lot.
>
> Sent with [ProtonMail](https://protonmail.com) Secure Email.
>       [[alternative HTML version deleted]]
>
> ______________________________________________
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

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