Greetings, I'm having some difficulties with evaluating very long expressions (Windows/Linux 2.0.1), as seen below, and would greatly appreciate any help, thoughts or work arounds. Let's say that I wanted to see what I would get if I added 1 to itself 498 times. One way of doing this would be to evaluate the expression 1+1+1+...
> eval(parse(text = paste(rep(1, 498), collapse = "+"))) [1] 498 However, if we try this with 499+ items we get no answer: > a <- eval(parse(text = paste(rep(1, 499), collapse = "+"))) > a Error: Object "a" not found And if this eval is passed to any other function, that function exits without error and without returning and object. So it seems that we've reached some upper limit of evaluation terms. While the parser is able to correctly create the long expression, eval does not successfully evaluate it. My problem is that since the evaluator does not return an object, error, or warning, I'm not able to easily code around this problem. Also, I've thought of no easy way to "count" the terms in the expression to see whether we've breached the upper limit or not. If I were able to see if the eval would work on a particular expression, one thing I had considered was to make an eval.long wrapper that peels terms off the right hand side of an overly-long expression until every sub-expression is legal. Thus, to count to 600 I could just add the first 497 terms with the next 103 terms. >eval(parse(text = paste(rep(1, 497), collapse = "+"))) + eval(parse(text = paste(rep(1, 103), collapse = "+"))) [1] 600 But without an error or way of figuring out if the expression would even be evaluated, I'm not sure how to know when to start or stop the peeling process. It also may become more complicated when parentheses are introduced. Any help would be greatly appreciated. Thanks, Robert platform i386-pc-mingw32 arch i386 os mingw32 system i386, mingw32 status major 2 minor 0.1 year 2004 month 11 day 15 language R Robert McGehee Geode Capital Management, LLC 53 State Street, 5th Floor | Boston, MA | 02109 Tel: 617/392-8396 Fax:617/476-6389 mailto:[EMAIL PROTECTED] This e-mail, and any attachments hereto, are intended for use by the addressee(s) only and may contain information that is (i) confidential information of Geode Capital Management, LLC and/or its affiliates, and/or (ii) proprietary information of Geode Capital Management, LLC and/or its affiliates. If you are not the intended recipient of this e-mail, or if you have otherwise received this e-mail in error, please immediately notify me by telephone (you may call collect), or by e-mail, and please permanently delete the original, any print outs and any copies of the foregoing. Any dissemination, distribution or copying of this e-mail is strictly prohibited. ______________________________________________ R-devel@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
