Backtest trading strategies

-----Original Message-----
From: r-sig-finance-bounces at stat.math.ethz.ch 
[mailto:r-sig-finance-bounces at stat.math.ethz.ch] On Behalf Of 
Gabor Grothendieck
Sent: Saturday, November 26, 2005 8:14 AM
To: paul sorenson
Cc: r-sig-finance at stat.math.ethz.ch
Subject: Re: [R-sig-finance] Backtest trading strategies

On 11/26/05, paul sorenson <sourceforge at metrak.com> wrote:

Gabor Grothendieck wrote:

On 11/26/05, Rob Steele <rfin.20.phftt at xoxy.net> wrote:

Neuro LeSuperH?ros wrote:

Hello,

I understand the utility of MySQL for data storage.  But why is 
Python essential?  What does it do that R can't do for system 
creation/calculation?

Thanks

Python is great for parsing data from wherever you get it and 
populating databases.  MySQL is ideal for the 
write-once-read-thereafter scenario that research 

implies.  You can 

use R for the initial data marshaling if you'd rather not learn 
another language but Python seems like a better fit for 

that sort of 

thing.  It's a scripting language that integrates more naturally 
into its host environment.  For analysis and 

visualization however, R absolutely rules.

I don't use MySQL so won't comment on that part but for 

parsing data 

I have found R to have everything I need.  I used to use perl
but now use R exclusively.    R's string manipulation includes
regular expressions and the vector processing often simplifies 
string manipulation by eliminating loops over lines or vectors of 
strings.

To me its much easier to maintain code if its all in one language 
and moving to R has enabled me to replace a bunch of perl, batch 
files and other statistical software with R which really 

helps clean 

it all up.  (Actually I still have some Windows batch files, see 
http://cran.r-project.org/contrib/extra/batchfiles/, but they are 
only for generic configuration utilities and nothing 

specific to any 

application.)

Each to their own I guess.  I happen to be much more familiar with 
Python than R and often use it to grab data in various 

formats which R 

won't read.  I wouldn't dream of using an MSDOS batch file.  As I 
learn more about R, I tend to do more in it but I couldn't imagine 
myself parsing dodgy HTML, for example, with it.

Actually I use R for parsing HTML and for parsing XML too.  I 
do agree by Rob that it would be nice if R worked better with 
shells and also wish I could write small self contained 
executables in R like one can in tcl and Python.