[R] finding those elements of listA that are found in listB

John Sorkin JSorkin at grecc.umaryland.edu
Thu Sep 17 04:43:04 CEST 2015


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
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University of Maryland School of Medicine Division of Gerontology and Geriatric Medicine
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