After reading a data.frame using, such as a <- read.spss("data.sav") I want to give the column index 'i', or a[i] to a function, which after some calculation, should print out the results to the standard output. I am struggling how to access the data itself, as e.g. sum(a[i]) does not work in this context. In addition I need to know the name of the variable within the function in order to generate a meaningful output, and have not found any way to obtain the name of the variable. Thanks for your input, Berthold -------------- next part -------------- A non-text attachment was scrubbed... Name: berthold.kramm.vcf Type: text/x-vcard Size: 214 bytes Desc: Card for Dr. Berthold Kramm Url : https://stat.ethz.ch/pipermail/r-help/attachments/20011127/318db43d/berthold.kramm.vcf
"Dr. Berthold Kramm" wrote:> > After reading a data.frame using, such as a <- read.spss("data.sav") > I want to give the column index 'i', or a[i] to a function, which after > some calculation, should print out the results to the standard output. > > I am struggling how to access the data itself, as e.g. sum(a[i])sum(a[,i])> does > not work in this context. In addition I need to know the name of the > variable within the function in order to generate a meaningful output, > and have not found any way to obtain the name of the variable.deparse(substitute(x)) Uwe Ligges -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
On Tue, 27 Nov 2001 14:32:27 +0100, you wrote in message <3C0395EB.4E95CDA6 at epost.de>:>After reading a data.frame using, such as a <- read.spss("data.sav") >I want to give the column index 'i', or a[i] to a function, which after >some calculation, should print out the results to the standard output. > >I am struggling how to access the data itself, as e.g. sum(a[i]) does >not work in this context. In addition I need to know the name of the >variable within the function in order to generate a meaningful output, >and have not found any way to obtain the name of the variable.Data frames are lists that act a lot like matrices. To get at column i, use a[,i] (i.e. all rows of column i, in matrix notation) or a[[i]] (i.e. list element i). If you use a[i] you get a data frame that consists only of column i, which is probably not what you want to work with. You want to extract the column into a vector. I recommend always using the matrix notation when you want numerical columns. Only use list notation when you are extracting a named column, i.e. use a$somecol rather than a[,'somecol']. To get the name of column i, use names(a)[i]. Duncan Murdoch -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._