Re: [R] vectorisation suggestion

From: <>
Date: Tue 21 Jun 2005 - 06:31:29 EST

v3 <- numeric()
v3[v1] <- table(v2)[v1]


James Holtman "What is the problem you are trying to solve?" Executive Technical Consultant -- Convergys Labs
+1 (513) 723-2929
                      Federico Calboli                                                                                                     
                      <f.calboli@imperial.a        To:       r-help <>                                             
            >                        cc:                                                                                     
                      Sent by:                     Subject:  [R] vectorisation suggestion                                                  
                      06/20/2005 16:15                                                                                                     

Hi All,

I am counting the number of occurrences of the terms listed in one vector in another vector.

My code runs:

for( i in 1:length(vector3)){

   vector3[i] = sum(1*is.element(vector2, vector1[i])) }


vector1 = vector containing the terms whose occurrences I want to count vector2 = made up of a number of repetitions of all the elements of vector1
vector3 = a vector of NAs that is meant to get the result of the counting

My problem is that vector1 is about 60000 terms, and vector2 is 620000... can anyone suggest a faster code than the one I wrote?


Federico Calboli

Federico C. F. Calboli
Department of Epidemiology and Public Health
Imperial College, St. Mary's Campus
Norfolk Place, London W2 1PG

Tel +44 (0)20 75941602   Fax +44 (0)20 75943193

f.calboli [.a.t]
f.calboli [.a.t]

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Received on Tue Jun 21 06:41:09 2005

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