R help - Nov 2007 - Romoving elements from a vector. Looking for the opposite of c(), New user

Hi

I have three vectors say x, y, z. One of them, x contains observations
on a variable. To x I want to append all observations from y and
remove all from z. For appending c() is easily used

x <- c(x,y)

But how do I remove all observations in z from x? You can say I am
looking for the opposite of c().

Best regards

On Nov 15, 2007, at 9:15 AM, Thomas Fr??jd wrote:
> Hi
>
> I have three vectors say x, y, z. One of them, x contains observations
> on a variable. To x I want to append all observations from y and
> remove all from z. For appending c() is easily used
>
> x <- c(x,y)
>
> But how do I remove all observations in z from x? You can say I am
> looking for the opposite of c().
If you are looking for the opposite of c, provided you want to remove  
the first part of things, then perhaps this would work:

z<-c(x,y)
z[-(1:length(x))]

However, if you wanted to remove all appearances of elements of x  
from c(x,y), regardless of whether those elements appear in the x  
part of in the y part, I think you would want:

z[!z %in% x]

Probably there are other ways.

Welcome to R!
> Best regards
Haris Skiadas
Department of Mathematics and Computer Science
Hanover College

Not sure i explained it good enough. Ill try with an example

say

x=[3,3,4,4,4,4,5,5,6,8]
z=[3,4,4,5,5]

what i want to get after removing z from x is something like
x=[3,4,4,6,8]


On Nov 15, 2007 3:29 PM, Charilaos Skiadas <cskiadas at gmail.com>
wrote:
>
>
> On Nov 15, 2007, at 9:15 AM, Thomas Fr??jd wrote:
>
> > Hi
> >
> > I have three vectors say x, y, z. One of them, x contains observations
> > on a variable. To x I want to append all observations from y and
> > remove all from z. For appending c() is easily used
> >
> > x <- c(x,y)
> >
> > But how do I remove all observations in z from x? You can say I am
> > looking for the opposite of c().
>
> If you are looking for the opposite of c, provided you want to remove
> the first part of things, then perhaps this would work:
>
> z<-c(x,y)
> z[-(1:length(x))]
>
> However, if you wanted to remove all appearances of elements of x
> from c(x,y), regardless of whether those elements appear in the x
> part of in the y part, I think you would want:
>
> z[!z %in% x]
>
> Probably there are other ways.
>
> Welcome to R!
>
> > Best regards
>
> Haris Skiadas
> Department of Mathematics and Computer Science
> Hanover College
>
> ______________________________________________
> 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.
>

Thomas Fr??jd wrote:
>Not sure i explained it good enough. Ill try with an example
>
>say
>
>x=[3,3,4,4,4,4,5,5,6,8]
>z=[3,4,4,5,5]
>
>what i want to get after removing z from x is something like
>x=[3,4,4,6,8]
>
>
>On Nov 15, 2007 3:29 PM, Charilaos Skiadas <cskiadas at gmail.com>
wrote:
>  
>
>>On Nov 15, 2007, at 9:15 AM, Thomas Fr??jd wrote:
>>
>>    
>>
>>>Hi
>>>
>>>I have three vectors say x, y, z. One of them, x contains
observations
>>>on a variable. To x I want to append all observations from y and
>>>remove all from z. For appending c() is easily used
>>>
>>>x <- c(x,y)
>>>
>>>But how do I remove all observations in z from x? You can say I am
>>>looking for the opposite of c().
>>>      
>>>
>>If you are looking for the opposite of c, provided you want to remove
>>the first part of things, then perhaps this would work:
>>
>>z<-c(x,y)
>>z[-(1:length(x))]
>>
>>However, if you wanted to remove all appearances of elements of x
>>from c(x,y), regardless of whether those elements appear in the x
>>part of in the y part, I think you would want:
>>
>>z[!z %in% x]
>>
>>Probably there are other ways.
>>
>>Welcome to R!
>>
>>    
>>
>>>Best regards
>>>      
>>>
>>Haris Skiadas
>>Department of Mathematics and Computer Science
>>Hanover College
>>
>>______________________________________________
>>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.
>>
>>    
>>
>
>______________________________________________
>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.
>
>
>
>  
>
Hi,

you may try this :

x=[3,3,4,4,4,4,5,5,6,8]
z=c(3,4,4,5,5)

 f1 <- function(vec,toremove){
+
+   for(elem in toremove){
+     temp <- grep(elem,vec)[1]
+     if(!is.na(temp)) vec <- vec[-temp]
+   }
+
+   return(vec)
+ }

 > f1(x,z)
[1] 3 4 4 6 8

Regards,

Thibaut.

-- 
######################################
Thibaut JOMBART
CNRS UMR 5558 - Laboratoire de Biom?trie et Biologie Evolutive
Universite Lyon 1
43 bd du 11 novembre 1918
69622 Villeurbanne Cedex
T?l. : 04.72.43.29.35
Fax : 04.72.43.13.88
jombart at biomserv.univ-lyon1.fr
http://lbbe.univ-lyon1.fr/-Jombart-Thibaut-.html?lang=en
http://pbil.univ-lyon1.fr/software/adegenet/

Try this.  xx and zz are the same as x and z except
they have a sequence number appended.  We then do
a setdiff and remove the sequence numbers.
> xx <- paste(x, seq(x) - match(x, x))
> zz <- paste(z, seq(z) - match(z, z))
> dd <- setdiff(xx, zz)
> as.numeric(sub(" .*", "", dd))
[1] 3 4 4 6 7 8 8 9


On Nov 15, 2007 11:09 AM, Thomas Fr??jd <tfrojd at gmail.com>
wrote:
> Not sure i explained it good enough. Ill try with an example
>
> say
>
> x=[3,3,4,4,4,4,5,5,6,8]
> z=[3,4,4,5,5]
>
> what i want to get after removing z from x is something like
> x=[3,4,4,6,8]
>
>
> On Nov 15, 2007 3:29 PM, Charilaos Skiadas <cskiadas at gmail.com>
wrote:
> >
> >
> > On Nov 15, 2007, at 9:15 AM, Thomas Fr??jd wrote:
> >
> > > Hi
> > >
> > > I have three vectors say x, y, z. One of them, x contains
observations
> > > on a variable. To x I want to append all observations from y and
> > > remove all from z. For appending c() is easily used
> > >
> > > x <- c(x,y)
> > >
> > > But how do I remove all observations in z from x? You can say I
am
> > > looking for the opposite of c().
> >
> > If you are looking for the opposite of c, provided you want to remove
> > the first part of things, then perhaps this would work:
> >
> > z<-c(x,y)
> > z[-(1:length(x))]
> >
> > However, if you wanted to remove all appearances of elements of x
> > from c(x,y), regardless of whether those elements appear in the x
> > part of in the y part, I think you would want:
> >
> > z[!z %in% x]
> >
> > Probably there are other ways.
> >
> > Welcome to R!
> >
> > > Best regards
> >
> > Haris Skiadas
> > Department of Mathematics and Computer Science
> > Hanover College
> >
> > ______________________________________________
> > 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.
> >
>
> ______________________________________________
> 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.
>

And here is a slightly shorter variation that encodes the
sequence number as the last two digits and then
removes it at the end:

xx <- 100 * x + seq(x) - match(x, x)
zz <- 100 * z + seq(z) - match(z, z)
setdiff(xx, zz) %/% 100


On Nov 15, 2007 4:54 PM, Gabor Grothendieck <ggrothendieck at gmail.com>
wrote:
> Try this.  xx and zz are the same as x and z except
> they have a sequence number appended.  We then do
> a setdiff and remove the sequence numbers.
>
> > xx <- paste(x, seq(x) - match(x, x))
> > zz <- paste(z, seq(z) - match(z, z))
> > dd <- setdiff(xx, zz)
> > as.numeric(sub(" .*", "", dd))
> [1] 3 4 4 6 7 8 8 9
>
>
>
> On Nov 15, 2007 11:09 AM, Thomas Fr??jd <tfrojd at gmail.com> wrote:
> > Not sure i explained it good enough. Ill try with an example
> >
> > say
> >
> > x=[3,3,4,4,4,4,5,5,6,8]
> > z=[3,4,4,5,5]
> >
> > what i want to get after removing z from x is something like
> > x=[3,4,4,6,8]
> >
> >
> > On Nov 15, 2007 3:29 PM, Charilaos Skiadas <cskiadas at
gmail.com> wrote:
> > >
> > >
> > > On Nov 15, 2007, at 9:15 AM, Thomas Fr??jd wrote:
> > >
> > > > Hi
> > > >
> > > > I have three vectors say x, y, z. One of them, x contains
observations
> > > > on a variable. To x I want to append all observations from y
and
> > > > remove all from z. For appending c() is easily used
> > > >
> > > > x <- c(x,y)
> > > >
> > > > But how do I remove all observations in z from x? You can
say I am
> > > > looking for the opposite of c().
> > >
> > > If you are looking for the opposite of c, provided you want to
remove
> > > the first part of things, then perhaps this would work:
> > >
> > > z<-c(x,y)
> > > z[-(1:length(x))]
> > >
> > > However, if you wanted to remove all appearances of elements of x
> > > from c(x,y), regardless of whether those elements appear in the x
> > > part of in the y part, I think you would want:
> > >
> > > z[!z %in% x]
> > >
> > > Probably there are other ways.
> > >
> > > Welcome to R!
> > >
> > > > Best regards
> > >
> > > Haris Skiadas
> > > Department of Mathematics and Computer Science
> > > Hanover College
> > >
> > > ______________________________________________
> > > 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.
> > >
> >
> > ______________________________________________
> > 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.
> >
>