R devel - Apr 2014 - Please make Pre-3.1 read.csv (type.convert) behavior available

Hi,

We at 0xdata use Java and R together, and the new behavior for read.csv has
made R unable to read the output of Java?s Double.toString().

This, needless to say, is disruptive for us.  (Actually, it was downright
shocking.)

+1 for restoring old behavior.

Thanks,
Tom

On 26/04/2014, 12:23 AM, Tom Kraljevic wrote:
>
> Hi,
>
> We at 0xdata use Java and R together, and the new behavior for read.csv has
> made R unable to read the output of Java?s Double.toString().
It may be less convenient, but it's certainly not "unable".  Use
colClasses.

>
> This, needless to say, is disruptive for us.  (Actually, it was downright
shocking.)
It wouldn't have been a shock if you had tested pre-release versions. 
Commercial users of R should be contributing to its development, and 
that's a really easy way to do so.

Duncan Murdoch
>
> +1 for restoring old behavior.

On Fri, Apr 25, 2014 at 09:23:23PM -0700, Tom Kraljevic wrote:
> This, needless to say, is disruptive for us.  (Actually, it was downright
shocking.)
It WAS somewhat shocking.  I trust the R core team to get things
right, and (AFAICT) they nearly always do.  This was an exception, and
shocking mostly in that it was so obviously wrong to completely
discard all possibility of backwards compatibility.

The old type.convert() functionality worked fine and was very useful,
so the *obviously* right thing to do would be to at least retain the
old behavior as a (non-default) option.

Reproducing the old behavior in user R code is not simple.  For
anybody else stuck with this, you can do it (probably inefficiently)
with the two functions below.  Create your own version of read.table()
that calls the dtk.type.convert() below instead of the stock
type.convert().  It's not pretty, but that will do it.


dtk.type.convert <- function(xx ,... ,ignore.signif.p=TRUE) { 
   # Add backwards compatibility to R 3.1's "new feature": 
   if(ignore.signif.p && all(dtk.can.be.numeric(xx ,ignore.na.p=TRUE)))
{
      if(all(is.na(xx))) type.convert(xx ,...) 
      else methods::as(xx ,"numeric")  
   } else type.convert(xx ,...) 
} 

dtk.can.be.numeric <- function(xx ,ignore.na.p=TRUE) { 
   # Test whether a value can be converted to numeric without becoming NA. 
   # AKA, can this value be usefully represented as numeric? 
   # Optionally ignore NAs already present in the incoming data. 

   old.warn <- options(warn = -1) ; on.exit(options(old.warn)) 
   aa <- !is.na(as.numeric(xx)) 
   if(ignore.na.p) (is.na(xx) | aa) else aa 
}

-- 
Andrew Piskorski <atp at piskorski.com>