Daniel, thanks for the answer. I will try to make myself i little bit clearer. Doing step by step I would have (using a loop trough the lines of 'A'):
1. AA[1] is 4. As so, I would have to compare A1[1] = 20 and A2[1] =3 with B1 B2 B3 B[3,2:4] 7 11 NA beacause BB[3]=4. Since there is no match, this would retrieve me a zero. The same would happen with AA[2]. For AA[3] I have AA A1 A2 [3,] 4 11 7 Since both A1[3] = 20 and A2[3] =3 match with B[3,2:4] this would retrieve me 1. 2. For AA[4:5] i would have to compare each line with B[1:2,2:4]. That is, for AA[4]=2 i have a match with BB[1] and BB[2]. Then I have to compare A1 A2 [4,] 5 5 with B1 B2 B3 B[1,2:4] 5 3 12 and B1 B2 B3 B[2,2:4] 11 12 13 Again, for A1[4] and A2[4] and would have no match. But A1[5] and A1[5] match with B2[1] and B1[1]. 3. And so on for the other lines of A. The problem is that if I perform that as a loop it really takes to long. Hope i could make it clearer. -- View this message in context: http://r.789695.n4.nabble.com/Big-data-and-column-correspondence-problem-tp3694912p3695795.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@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.