I think you are looking for match or %in% (which is a based on match)
> a <- sample(12)
> b <- c(1, 3, 5, 11, 17)
> a
[1] 10 8 1 4 7 3 6 11 2 12 5 9
> b
[1] 1 3 5 11 17
> [1] 1
> match(a, b)
[1] NA NA 1 NA NA 2 NA 4 NA NA 3 NA
> match(a, b, 0)
[1] 0 0 1 0 0 2 0 4 0 0 3 0
> match(b, a)
[1] 3 6 11 8 NA
> match(b, a, 0)
[1] 3 6 11 8 0
> a %in% b
[1] FALSE FALSE TRUE FALSE FALSE TRUE FALSE TRUE FALSE FALSE TRUE FALSE
> b %in% a
[1] TRUE TRUE TRUE TRUE FALSE
>
Rich
On Wed, Sep 16, 2015 at 10:43 PM, John Sorkin <jsor...@grecc.umaryland.edu>
wrote:
> I have two structures. I think they are lists, but I am not sure. Both
> structures contain integers. I am trying to find those members of list b
> that are found in list a. I have tried to perform the search using grep,
> but I get an error. Please see code below. I would appreciate knowing how
> to search listB for any element in listA
> Thanks
> John
>
>
> > str(listA)
> int [1:42] 13083 13705 14123 14168 14382 14652 14654 14678 14817 14822 ...
> > str(listB)
> int [1:633] 13083 13083 13083 13083 13083 13083 13705 13705 13705 13705
> ...
> > grep(listA,listB)
> [1] 1 2 3 4 5 6
> Warning message:
> In grep(listA, listB) :
> argument 'pattern' has length > 1 and only the first element will be used
>
>
>
>
>
>
>
>
>
> John David Sorkin M.D., Ph.D.
> Professor of Medicine
> Chief, Biostatistics and Informatics
> University of Maryland School of Medicine Division of Gerontology and
> Geriatric Medicine
> Baltimore VA Medical Center
> 10 North Greene Street
> GRECC (BT/18/GR)
> Baltimore, MD 21201-1524
> (Phone) 410-605-7119
> (Fax) 410-605-7913 (Please call phone number above prior to faxing)
>
>
> Confidentiality Statement:
> This email message, including any attachments, is for ...{{dropped:16}}
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