search for: rs154354

Dear all, I need to read an ASCII file with diffent length lines. This is what is contained in the file gene.txt: 1st line ID description snp_id genotype 2nd line 10003 Low rs152240 3rd line 10003 Moderate rs189011 TC 4th line 10004 Conservative rs152240 GC 5th line 10004 Bad rs154354 6th line 10013 Bad rs152240 7th line 10019 Conservative rs152240 AC etc... This is what I would like to obtain in R: ID description snp_id genotype 10003 Low rs152240 NA 10003 Moderate rs189011 TC 10004 Conservative rs152240 G...