Re: [R] Evaluating a string
On Jul 2, 2010, at 2:05 AM, Joshua Wiley wrote: Hello Jonathan, You can use eval() and parse(), although there may be better ways of getting to your end goal > do.call(operator, list(a,b)) [1] 1 (assuming you have not inherited a series of character strings held in objects that should be run as commands). At any rate, this works: a <- 3 b <- 2 operator <- "-" statement_string <- paste(a, operator, b, sep="") eval(parse(text = statement_string)) Best regards, Josh On Thu, Jul 1, 2010 at 2:54 PM, Jonathan Greenberg wrote: Rhelpers: How do I get R to evaluate a string, as if it was an R statement, e.g.: a=3 b=2 operator="-" statement_string=paste(a,operator,b,sep="") --j David Winsemius, MD West Hartford, CT __ 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.
Re: [R] Evaluating a string
Hello Jonathan, You can use eval() and parse(), although there may be better ways of getting to your end goal (assuming you have not inherited a series of character strings held in objects that should be run as commands). At any rate, this works: a <- 3 b <- 2 operator <- "-" statement_string <- paste(a, operator, b, sep="") eval(parse(text = statement_string)) Best regards, Josh On Thu, Jul 1, 2010 at 2:54 PM, Jonathan Greenberg wrote: > Rhelpers: > > How do I get R to evaluate a string, as if it was an R statement, e.g.: > > a=3 > b=2 > operator="-" > statement_string=paste(a,operator,b,sep="") > > --j > > __ > 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. > -- Joshua Wiley Ph.D. Student, Health Psychology University of California, Los Angeles http://www.joshuawiley.com/ __ 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] Evaluating a string
Rhelpers: How do I get R to evaluate a string, as if it was an R statement, e.g.: a=3 b=2 operator="-" statement_string=paste(a,operator,b,sep="") --j __ 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.
