--- Begin Message ---Dear Mr Gunter,with a slight correction: z <- array(1:24,dim=2:4) d <- dim(z) ix <- lapply(d[-1], seq_len) do.call("[", c(list(z),1,ix)) [,1] [,2] [,3] [,4] [1,] 1 7 13 19 [2,] 3 9 15 21 [3,] 5 11 17 23 your suggestion worked and is exactly what I wanted! Thank You very much indeed! I want to get rid of all eval(parse) constructs in my code, and this was the greatest obstacle I had. Now I will be able to do this. As they say, eval parse in the code is just lack on knowledge. Best regards, Martin >-------- Оригинално писмо -------- >От: Florent D. >Относно: Re: [R] avoiding eval parse with indexing >До: Bert Gunter >Изпратено на: Неделя, 2013, Май 26 18:07:26 EEST > > >library(abind) >asub(x, 1, 1) > >On Sun, May 26, 2013 at 10:43 AM, Bert Gunter wrote: >> Martin: >> >> Well, assuming I understand, one approach would be to first get the >> dim attribute of the array and then create the appropriate call using >> that: >> >>> z <- array(1:24,dim=2:4) >>> d <- dim(z) >>> ix <-lapply(d[-c(1,1)],seq_len) >>> do.call("[", c(list(z),1,1,ix)) >> [1] 1 7 13 19 >> >> Is that what you want? >> >> -- Bert >> >> >> >> On Sun, May 26, 2013 at 6:56 AM, Martin Ivanov wrote: >>> Hello, >>> I would like to get an advice on how the notorious eval(parse()) construct >>> could possibly >>> be avoided in the following example. I have an array x, which can have >>> different number of dimensions, >>> but I am only interested in extracting, say, the first element of the >>> first dimension. Currently I achieve this >>> in this way: >>> >>> eval(parse(text=paste0("x[1", paste(rep(", ", >>> length(dim(x)) - 1), collapse=""), "]"))) >>> >>> Is it possible to avoid the eval parse here? How? >>> >>> Best regards, >>> >>> Martin >>> >>> ______________________________________________ >>> 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. >> >> >> >> -- >> >> Bert Gunter >> Genentech Nonclinical Biostatistics >> >> Internal Contact Info: >> Phone: 467-7374 >> Website: >> http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm >> >> ______________________________________________ >> 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. >
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______________________________________________ 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.
