[R] Sum two Vectors of different length

Petr PIKAL petr.pikal at precheza.cz
Fri Aug 3 15:41:45 CEST 2012


Hi

Your description is quite long but almost uninformative about what you 
really want. 

You do not say which values you want to sum but you say it is completely 
equal which value you want to add to what and what shall be the final 
vector length

Based on this I would just use simple "+"

x<-1:10
y<-1:9
x+y
 [1]  2  4  6  8 10 12 14 16 18 11
Warning message:
In x + y : longer object length is not a multiple of shorter object length

warning message is not an error and tells you that the shorter vector is 
recycled e.g. 1,2 or 3 elements are used twice for the calculation. 
Therefore the last value is 11 which is 10 from x vector + 1 from y 
vector.

If you have some other constrains and failed to tell us please do it to 
get some better suited answer.

Regards
Petr

> 
> Dear all,
> in one part of my code I want to sum two vectors element-wise
> the problem is that either the 1st vector or the 2nd vector always have 
> one or two less elements
> 
> example of my problem
> 
> In TotalVector + 
(datalist2[[1]]$dataset$Results[[j]]$Results[[time]]$Sweep) :
>   Länge des längeren Objektes
>          ist kein Vielfaches der Länge des kürzeren Objektes
> Browse[1]> str(TotalVector)
>  int [1:10308] 3032 3048 3075 2978 3026 3012 2933 2987 3063 3038 ...
> Browse[1]> 
str(datalist2[[1]]$dataset$Results[[j]]$Results[[time]]$Sweep)
>  int [1:10307] 2 1 3 1 5 6 3 1 0 2 ...
> 
> 
> as you can see the two vectors differ only in one element. As the sample 

> is quite large it would be the same if I ignore the one extra element.
> There are times though that the missing elements can be 2 or 3 (but 
always
> the number is small enough so to be ignored)
> 
> 
> The major concern is that this "difference" can be either on the fist 
> vector or either on the second vector. If I try to solve that with 
simple 
> if statements the code gets too much of spaghetti... Is there a simple 
way
> when there is this length difference 
> 
> 
> either to 
> 
> 
> a. Ignore the extra elements
> -or-
> 
> b. Add the elements missing to the vector with the smaller length( one 
can
> just duplicate some of the existing values to reach the needed length)
> 
> How I can do either a or b?
> 
> I would like to thank you in advance for your help
> 
> Regards
> Alex
> 
>    [[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at r-project.org 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.



More information about the R-help mailing list