all occurences of an element in a vector

To convert this from the abstract to the real ...

In what sense does %in% return only the first occurrence of an element?
See:
foo <- c('1','n','m','e','m','n','n','u')
foo[foo %in% c('m','n')]
[1] "n" "m" "m" "n" "n"
cbind(foo, foo %in% c('m','n'))
foo        
[1,] "1" "FALSE"
[2,] "n" "TRUE" 
[3,] "m" "TRUE" 
[4,] "e" "FALSE"
[5,] "m" "TRUE" 
[6,] "n" "TRUE" 
[7,] "n" "TRUE" 
[8,] "u" "FALSE"

It sure looks to me like %in% identifies all the occurrences of
[m,n] in [1,n,m,e,m,n,n,u]

Or did you mean [m,n] appearing next to each other in that order???
Don MacQueen

Lawrence Livermore National Laboratory
7000 East Ave., L-627
Livermore, CA 94550
925-423-1062

On 5/21/12 7:33 AM, "carol white" <wht_crl at yahoo.com> wrote:

>like searching m or [m,n] in [1,n,m,e,m,n,n,u].
>
>I want the exact match of all occurrences of m and n in the last vector.
>Therefore, grep is not helpful as it will extract if there are also mm
>and mmm.
>
>Cheers,
>
>Carol
>
>
>________________________________
> From: Ista Zahn <istazahn at gmail.com>
>
>Cc: "r-help at stat.math.ethz.ch" <r-help at stat.math.ethz.ch>
>Sent: Monday, May 21, 2012 3:38 PM
>Subject: Re: [R] all occurences of an element in a vector
>
>Hi Carol,
>
>I'm not sure what a "sub-vector in a vector" is, but I think you might
>be looking for ?grep
>
>Best,
>Ista
>
>
>> Hi,
>> How do you identify all occurences of an element or a sub-vector in a
>>vector as opposed to match, %in%, and intersect which find the first
>>occurrence of an element?
>>
>> Cheers,
>>
>> Carol
>>
>>        [[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.
>	[[alternative HTML version deleted]]
>

all occurences of an element in a vector

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