[R] two questions for R beginners

Mario Valle mvalle at cscs.ch
Fri Feb 26 10:38:24 CET 2010


My difficulties:
1) Statistics :-) well, I'm learning.
2) Understand what is available *per subject area*. Something like the task view for
packages, should be compiled for basic commands/functions. Like: all things related to
string manipulation, all things related to number formatting, all *apply things, and so
on. Something similar is available for C runtime library functions (like in
http://msdn.microsoft.com/en-us/library/2aza74he(VS.71).aspx ) and is really useful, also
to expand the number of functions known.
3) The Diktakt-like: "avoid for loops!" without clear examples of alternatives. I have
found them later in the maillist, but at the beginning it is not simple, especially coming
from C/C++.
4) for statement behavior different from C/C++: for(i in 1:0) counts backward instead of
stopping.
5) missing small things like ++var

On the positive side:
- it is not too difficult to setup something simple to create a decent chart.
- it is possible to use for loops without feeling guilty. :-)
- documentation is very well done. Maybe some page are still clear only to who already
know the argument.
- there are zillions of courses/papers/tutorials to read
- after studying R by myself, now I'm becoming the local R expert, that from a workplace
point of view is not bad...

Hope it helps.
Ciao!
	mario


Ivan Calandra wrote:
> Since you want input from beginners, here are some thoughts
> 
> I had and still have two big problems with R:
> - this vectorization thing. I've read many manuals (including R 
> inferno), but I'm still not completely clear about it. In simple 
> examples, it's fine. But when it gets a bit more complex, then...
> Related to it, the *apply functions are still a bit difficult to 
> understand. When I have to use them, I just try one and see what 
> happens. I don't understand them well enough to know which one I need.
> - the second problem is where to find the functions/packages I need. 
> There are many options, and that's actually the problem. R Wiki, Rseek, 
> RSiteSearch, Crantastic, etc... When you start with R, you discover that 
> the capabilities of R are almost unlimited and you don't really know 
> where to start, where to find what you need.
> 
> As noted in earlier posts, the mailing list is really great, but some 
> people are really hard with beginners. It was noted in a discussion a 
> few days ago, but it looks like some don't realize how difficult it is 
> at the beginning to formulate a good question, clear, with 
> self-contained example and so on. Moreover, not everybody speaks English 
> natively. I don't mean that you must help, even when the question is 
> really vague and not clear and whatever. I'm just saying that if you 
> don't want to help (whatever the reason), you don't have to say it 
> badly. But in any cases, the mailing list is still really helpful. As 
> someone noted (sorry I erased the email so I don't remember who), it 
> might be a good idea to split it.
> 
> Hope that's what you wanted
> Ivan
> 
> 
> Le 2/26/2010 08:39, Dieter Menne a écrit :
>> Patrick Burns wrote:
>>    
>>> * What were your biggest misconceptions or
>>> stumbling blocks to getting up and running
>>> with R?
>>>
>>>
>>>      
>> (This derives partly from teaching)
>>
>> The fact that this xapply-stuff was not idempotent (worse: not always) and
>> that you need a monster like do.call() to straighten this out. Nowadays,
>> plyr comes close.
>>
>> The concept of environment. With S it was worse, though.
>>
>> That you cannot change values "passed by reference". I noted that the latter
>> is no problem for students who have not worked with c(++/#) before. That
>> there is only one return-result in functions.
>>
>> "[" and the likes as an operator.
>>
>> 10 years ago, when I started, the message was: S4 is the future, S3 is
>> legacy. So I learned S4. Only to never use is in self-written code later.
>> Might be different for BioConductor people.
>>
>> That sometimes you can use vectors not in data= (lattice), and sometimes not
>> (ggplot2). Still a VERY confusing inconsistency.
>>
>> The "why-does-this-not-print" FAQ.
>>
>> Why does par(oma..) not work with lattice?
>>
>> Dieter
>>
>>
>>
> 
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-- 
Ing. Mario Valle
Data Analysis and Visualization Group            | http://www.cscs.ch/~mvalle
Swiss National Supercomputing Centre (CSCS)      | Tel:  +41 (91) 610.82.60
v. Cantonale Galleria 2, 6928 Manno, Switzerland | Fax:  +41 (91) 610.82.82



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