[R] Data Manipulation Question

[Gray Calhoun]

This is probably far more discussion than the question warranted, but...

On Thu, Dec 3, 2009 at 11:14 PM, David Winsemius <dwinsemius at comcast.net> wrote:
>
> On Dec 3, 2009, at 10:52 PM, Gray Calhoun wrote:
>
>> The data import/export manual can elaborate on a lot of these; this is
>> all straightforward, although many people would prefer to use a
>> relational database for some of the things you mentioned.
>
> See Wickham's pithy response to this.

Sure.  My (indirect) point is that representing query results as
separate files is usually not the right approach, regardless of
statistical language/package one uses.

>
>> I'm not
>> aware of a "goto" command in R, though (although I could be wrong).
>
> In fairness to the OP, he did not ask if there were a go-to construct, but
> rather whether there were a "gosub" construct that supported "modular
> programming". My response would have been that calling modular functions
> (i.e., subroutines with defined arguments) is fundamental to R and the key
> to understanding how to use it with grace and efficiency. I would say that
> the concept of functional programming is to a much greater extent supported
> by R than by SAS, whose datastep mechanisms (as I remember them from earlier
> incarnation) in no way supported modular programming. I suspect that S and R
> arose precisely because of the mental straightjackets imposed by SAS.

>From the original: "Goto Start until File 1 Done."  But, yes, probably
unfair and certainly less informative than your response.

>
> --
> David.
>
>
>> --Gray
>>
>> On Thu, Dec 3, 2009 at 1:52 PM, John Filben <johnfilben at yahoo.com> wrote:
>>>
>>> Can R support data manipulation programming that is available in the SAS
>>> datastep?  Specifically, can R support the following:
>>> -          Read multiple dataset one record at a time and compare values
>>> from each; then base on if-then logic write to multiple output files
>>> -          Load a lookup table and then process a different file; based
>>> on if-then logic, access and lookup values in the table
>>> -          Support modular “gosub”programming
>>> -          Sort files
>>> -          Date math and conversions
>>> -          Would it be able to support the following type of logic:
>>> o   Start
>>> §  Read Record from File 1
>>> §  Read Record from File 2
>>> §  Match
>>> ·         If Key 1 <> Key 2 and Key 1 < Key 2, Write to output file A
>>> ·         If Key 1 = Key 2, Write to output file B
>>> ·         If Key 1 <> Key 2 and Key 1 > Key 2, Write to output file C§
>>>  Goto Start until File 1 Done
>>>  John Filben
>>> Cell Phone - 773.401.2822
>>> Email - johnfilben at yahoo.com
>>>
>>>
>>>
>>>       [[alternative HTML version deleted]]
>>>
>>>
>>> ______________________________________________
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>>>
>>>
>>
>> ______________________________________________
>> 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.
>
> David Winsemius, MD
> Heritage Laboratories
> West Hartford, CT
>
>