R help - Feb 2010 - Finding the difference between two vectors

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:
http://n4.nabble.com/Finding-the-difference-between-two-vectors-tp1460020p1460020.html
Sent from the R help mailing list archive at Nabble.com.

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: 
http://n4.nabble.com/Finding-the-difference-
> between-two-vectors-tp1460020p1460020.html
> Sent from the R help mailing list archive at Nabble.com.
> 
> ______________________________________________
> 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.