[R] Convert char vector to numeric table

[Prof. Brian Ripley]

Use a file() connection (no argument) or a textConnection.

file() is a powerful tool, often overlooked.

On Mon, 31 Mar 2003, Nurnberg-LaZerte wrote:

> I'm a great fan of read.table(), but this time the data had a lot of cruft. So I used readLines() and editted the char vector to eventually get something like this:
> "     23.4   1.5   4.2"
> "     19.1   2.2   4.1"
> and so on. To get that into a 3 col numeric table, I first just used:
> 
> writeLines(data,"tempfile")
> read.table("tempfile",col.names=c("A","B","C"))
> 
> Works fine, but writing to a temporary file seems ... inelegant?  And read.table() doesn't take a char vector as a file or connection argument. The following works but it seems like a lot of code: 
> 
> data <- sub(" +","",data)   		# remove leading blanks for strsplit
> data <- strsplit(data," +")   		# strsplit returns a list of char vectors
> ndata <- character(0)			# vectorize the list of char vectors
> for (ii in 1:length(data)) ndata <- c(ndata,data[[ii]])  
> ndata <- as.numeric(ndata)				
> dim(ndata) <- c(3,length(data))	  	
> data <- t(ndata)
> data.frame(A=data[,1],B=data[,2],C=data[,3])

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
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