[R] Python difflib R equivalent?

[Prof Brian Ripley]

On Thu, 28 Jul 2011, Bert Gunter wrote:

> Paul:
>
> 1. I do not know if any such library exists.

Not to my knowledge, and we have contemplated providing such 
functions.  But for files see e.g. tools::Rdiff, and generally R will 
not be a good way to do this sort of thing on files (since the 
flexibility of R's i/o via connections does have a cost)

> 2. However, if I understand correctly, one usually does this sort of
> thing in R with functions like ?match (or ?"%in%") and logical
> comparison operations like ?"==" .  Of course, for numeric
> comparisons, you need to be aware of R FAQ 7.31
>
> If you are interested in comparing what in R are character vectors,
> then various string operators, e.g. ?grep, ?regexp and character
> operation packages (e.g. gsubfn, stringr) may be of use.
>
> As usual, you are more likely to receive a helpful answer if you do as
> the posting guide requests and provide a small, reproducible example
> of the sort(s) of thing(s) you want to do.

Or at least a URI of examples you wish to emulate, which for difflib 
seem to be the sort of thing POSIX diff and friends are used for.

> Cheers,
> Bert
>
> On Thu, Jul 28, 2011 at 4:05 AM, Paul <newzealandspaul at gmail.com> wrote:
>> Hi,
>>
>> Does anyone know of a R library that is equivalent in functionality to
>> the Python standard libraries' difflib library? The python docs say
>> this about difflib:
>>
>> "This module provides classes and functions for comparing sequences.
>> It can be used for example, for comparing files, and can produce
>> difference information in various formats, including HTML and context
>> and unified diffs."
>>
>> http://docs.python.org/library/difflib.html
>>
>> Thanks,
>>
>> Paul
>>
>> ______________________________________________
>> R-help at 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.
>>
>
>
>
> -- 
> "Men by nature long to get on to the ultimate truths, and will often
> be impatient with elementary studies or fight shy of them. If it were
> possible to reach the ultimate truths without the elementary studies
> usually prefixed to them, these would not be preparatory studies but
> superfluous diversions."
>
> -- Maimonides (1135-1204)
>
> Bert Gunter
> Genentech Nonclinical Biostatistics
>
> ______________________________________________
> R-help at 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.
>

-- 
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