[R] Odp: Finding the difference between two vectors

[Petr PIKAL]

Hi

Option one

vec1<-sample(letters[1:10])
vec2<-vec1[-5]
vec2<-c(vec2,NA)
# missing position
mis<-which(!(vec1 %in% vec2))

 c(vec2[1:(mis-1)], NA,vec2[mis:((length(vec2)-1))])
 [1] "f" "e" "g" "d" NA  "j" "c" "i" "b" "h"

gives you desired vector. For two or more values missing it shall be 
rephrased probably by rle

Option two

mis<-which(!(vec1 %in% vec2))
vec2 <- vec1
vec2 [mis] <-NA

Which could be used in case of several values missing.

But I wonder what you want to achieve. It seems to me like you want to do 
something for which merge can be used.

See ?merge

Regards
Petr

 

r-help-bounces at r-project.org napsal dne 02.02.2010 16:34:23:

> 
> Hello everyone,
> I have two vectors having only one element different:
>                            vector1         vector2 
> vector1
> 
>                            TWC             TWC  
> TWC
>                            VFC              TWX  
> NA 
>                           VIA/B             VFC  
> VFC
>                           WHR             VIA/B  
> VIA/B
>                            WPO             WHR   --------->>>        WHR
>                            WYN             WPO  
> WPO
>                            WYNN          WYN  
> WYN
>                            YUM            WYNN  
> WYNN
>                            NA               YUM  
> YUM
> In that case, in the first vector, the value twx is missing . What I 
want to
> do is doing the following avoiding loop:
> putting the NA row in front of the TWX row as this would be the row 
where
> the value is missing. I don't know if there is any function doing this. 
I
> thought about using a which() function to retrieve all the missing 
elements
> index ( twx, 1 here) and insert them in the right index in the first 
vector
> but how can I insert in a vector, is there an appropriated function? 
thank
> you
> 
> -----
> Anna Lippel
> -- 
> View this message in context: 
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> between-two-vectors-tp1460020p1460020.html
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> 
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