From ripley at stats.ox.ac.uk  Wed Jul 27 08:59:21 2005
From: ripley at stats.ox.ac.uk (Prof Brian Ripley)
Date: Wed, 27 Jul 2005 07:59:21 +0100 (BST)
Subject: [Rd] R 2.1.1: read.table processes C-style escapes  (PR#8037)
In-Reply-To: <6.2.1.2.1.20050727141319.021c8c40@imaphost.wehi.edu.au>
References: <6.2.1.2.1.20050727141319.021c8c40@imaphost.wehi.edu.au>
Message-ID: <Pine.LNX.4.61.0507270757580.21618@gannet.stats>

This seems of historical interest only.

allowEscapes is currently (in R-devel, where development happens) an 
argument to read.table.

We do ask people to check the current version!

On Wed, 27 Jul 2005, Gordon Smyth wrote:

>
>> To: r-bugs at biostat.ku.dk
>> From: Gordon Smyth <smyth at wehi.edu.au>
>> Subject: R 2.1.1: read.table processes C-style escapes
>> Date: Wed, 27 Jul 2005 12:51:45 +1000
>>
>> In R 2.1.1, the default behaviour of scan() was changed to process all
>> C-style escapes, even when a delimiter was specified using the 'sep'
>> argument. A new argument 'allowEscapes' was introduced to turn this
>> processing off.
>>
>> Because read.table() calls scan(), read.table() inherits the new default
>> behaviour of scan() but without a way to turn it off. For example, reading
>> a file testdata.txt' containing
>>
>> X
>> A
>> \0
>> C
>>
>> produces
>>
>>> read.delim("testdata.txt")
>> [1] X
>> <0 rows> (or 0-length row.names)
>>
>> It seems that all the occurances of scan() within read.table() need to
>> have 'allowEscapes=FALSE' added to the argument string.
>
> Or, alternatively and perhaps better, scan() could regain some of its
> earlier behaviour, to process C-style escapes by default only when 'sep' is
> NULL or empty. It seems, to me at least, that C-style escape sequences make
> sense only in some sort of source code, and delimited text can't be source
> code.
>
> Gordon
>
>> Gordon
>>
>>> version
>>          _
>> platform i386-pc-mingw32
>> arch     i386
>> os       mingw32
>> system   i386, mingw32
>> status   Patched
>> major    2
>> minor    1.1
>> year     2005
>> month    07
>> day      22
>> language R
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
>

-- 
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)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595



[Rd] R 2.1.1: read.table processes C-style escapes (PR#8037)
Prof Brian Ripley