[R] R programming style

[Scillieri, John]

I second that, Code Complete is a great book! For anyone interested in
improving their code no matter what language, (it has a C++/Java-type
focus but is definitely applicable to R), it would definitely be a good
place to start.

I've read some negative reviews claiming that everything he writes is
'obvious' (use good variable names, short concise functions, limit
nested conditionals, etc) but on more than one occasion I've gone back
over the book and thought of new places to improve my code. 

HTH,
John 

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of Earl F. Glynn
Sent: Monday, February 11, 2008 2:30 PM
To: r-help at stat.math.ethz.ch
Subject: Re: [R] R programming style

"David Scott" <d.scott at auckland.ac.nz> wrote in message
news:alpine.LRH.1.00.0802112343200.27944 at stat12.stat.auckland.ac.nz...
>
> Can anyone provide further pointers to good style?

While not written for R specifically, the book "Code Complete:  A
Practical Handbook of Software Construction" (2nd Edition) discusses a
number of good concepts for writing good code in any language:
http://www.amazon.com/Code-Complete-Practical-Handbook-Construction/dp/0
735619670

In particular, Part IV "Statements" gives a number of useful suggestions
by type of statement, e.g., straight-line code, conditionals, loops, ...

There are some practices used in R that I think should be improved.  For
example, many years ago I was taught in a software engineering class
that the use of  "magic numbers" was a bad practice, yet we find magic
numbers used in R in many places.

Instead of using "1" or "2" in an "apply", I'll write something like
this trying for some sort of mnemonic

apply(x, BY.ROW<-1, sum)
or
apply(z, BY.COL<-2, mean)


I find BY.ROW or BY.COL to be more mnemonic than the magic numbers 1 and
2.

The "sides" 1, 2, 3, and 4 in an axis statement should have some sort of
mnemonic definition, too, perhaps:

axis(BOTTOM<-1, ...)

But I believe I was ostracized in this E-mail list the last time I
suggested such mnemonics instead of magic numbers.

efg
Earl F. Glynn
Bioinformatics
Stowers Institute for Medical Research

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