Oh, also thanks for the speed comparisons. Missed that in my first read-through. Very interesting and informative. BNC
-----Original Message----- From: Crombie, Burnette N Sent: Thursday, July 11, 2013 4:40 PM To: 'arun' Cc: R help Subject: RE: [R] create new matrix from user-defined function You understood me perfectly, and I agree is it easier to index using numbers than names. I'm just afraid if my dataset gets too big I'll mess up which index numbers I'm supposed to be using. "data.table()" looks very useful and a good way to approach the issue. Thanks. I really appreciate your (everyone's) help. BNC ______________________________________________ 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.