> as.list(expression( 2*3)) [[1]] 2 * 3 > as.list(quote( 2*3)) [[1]] `*`
[[2]] [1] 2 [[3]] [1] 3 > identical(as.list(expression( 2*3))[[1]],quote(2*3)) [1] TRUE expression() wraps the call into an expression object (as pointed out to me by Gabor Grothendieck). Bert Gunter Genentech Nonclinical Statistics -----Original Message----- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of blue sky Sent: Friday, February 19, 2010 9:43 AM To: r-h...@stat.math.ethz.ch Subject: [R] What is the difference between expression and quote when usedwith eval()? I made the following example to see what are the difference between expression and quote. But I don't see any difference when they are used with eval()? Could somebody let me know what the difference is between expression and quote? expr=expression(2*3) quo=quote(2*3) eval(expr) str(expr) class(expr) typeof(expr) mode(expr) attributes(expr) eval(quo) str(quo) class(quo) typeof(quo) mode(quo) attributes(quo) ______________________________________________ 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. ______________________________________________ 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.
