Dear group, Here is a data.frame, "lme":
> lme DESCRIPTION CLOSING.PRICE POSITION 4 PRIMARY NICKEL USD 04/06/10 25,755.7100 0 5 PRIMARY NICKEL USD 10/06/10 25,760.8600 0 6 PRM HGH GD ALUMINIUM USD 09/07/10 2,415.9000 0 8 SPCL HIGH GRADE ZINC USD 06/07/10 2,420.1000 -1 9 SPCL HIGH GRADE ZINC USD 07/07/10 2,420.4100 -1 10 SPCL HIGH GRADE ZINC USD 08/07/10 2,420.7300 1 11 SPCL HIGH GRADE ZINC USD 09/07/10 2,421.0500 1 12 SPCL HIGH GRADE ZINC USD 13/04/10 2,388.4300 0 13 SPCL HIGH GRADE ZINC USD 14/04/10 2,389.0000 0 14 SPCL HIGH GRADE ZINC USD 15/04/10 2,389.5700 0 15 SPCL HIGH GRADE ZINC USD 17/05/10 2,402.2900 0 16 SPCL HIGH GRADE ZINC USD 18/05/10 2,402.6400 -2 DESCRIPTION and CLOSING.PRICE are factors, POSITION is numeric. I want to sum POSITION by products, i.e. PRIMARY NICKEL, PRM HGH GD ALUMINIUM and SPCL HIGH GRADE ZINC. The problem is that, as you can see, there is a different date as a part of each product description. Can anyone tell me how to get rid of these dates so I can sum the position column? The number of rows is not fixed and will change every day. TY. ______________________________________________ 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.