R help - Sep 2010 - Some questions about string processing

Hi all

A couple of questions about string processing from someone who has only
scratched the surface so far.

1) I am wanting to send some strings into a function to allow flexibility
inside.  My first idea has been e.g.

auto_io <- function( var_string, factors ) {
#  e.g. var_string sent as "test_file.txt"  factors sent as "x1 +
x2 + x3"

# input
	data_name 				<- get( var_string )
	
#	term_list 				<- get( factors )
	
	resp_data 				<- read.table( data_name, header = TRUE )
		
# fit
	temp_model 			<-  lm( y ~ factors, data = resp_data )

	etc...

Neither the read.table() nor the lm() are working because in each case the
string is not converted or understood properly.  I'm sure this is possible
(and in fact probably easy) but haven't yet seen the light.  Could someone
illuminate me here?

2) I will be wanting to process strings as lists of strings.  For instance, I
might instead want to send factors above as "x1  x2  x3" and add the
"+" when I need them, or perhaps "*" instead, and also look
at sub-models by removing parts of the string etc.  What functions should I be
looking at here and are there any examples available?

Thanks in advance.  Feel free to CC me on your reply.


Michael Hopkins
Algorithm and Statistical Modelling Expert
 
Upstream
23 Old Bond Street
London
W1S 4PZ

Mob +44 0782 578 7220
DL   +44 0207 290 1326
Fax  +44 0207 290 1321

hopkins@upstreamsystems.com
www.upstreamsystems.com
 
IMPORTANT NOTICE
The information in this e-mail and any attached files is...{{dropped:22}}

Michael -
    You're doing too much work half the time, and not enough
the other half :-).  Try this (untested):

auto_io = function(data_name,factors){
    resp_data =  read.table(data_name, header = TRUE )
    temp_model = lm(formula(paste('y',factors,sep='~')) data =
resp_data )
                . . .

 					- Phil Spector
 					 Statistical Computing Facility
 					 Department of Statistics
 					 UC Berkeley
 					 spector at stat.berkeley.edu


On Fri, 24 Sep 2010, Michael Hopkins wrote:
>
>
> Hi all
>
> A couple of questions about string processing from someone who has only
scratched the surface so far.
>
> 1) I am wanting to send some strings into a function to allow flexibility
inside.  My first idea has been e.g.
>
> auto_io <- function( var_string, factors ) {
> #  e.g. var_string sent as "test_file.txt"  factors sent as
"x1 + x2 + x3"
>
> # input
> 	data_name 				<- get( var_string )
>
> #	term_list 				<- get( factors )
>
> 	resp_data 				<- read.table( data_name, header = TRUE )
>
> # fit
> 	temp_model 			<-  lm( y ~ factors, data = resp_data )
>
> 	etc...
>
> Neither the read.table() nor the lm() are working because in each case the
string is not converted or understood properly.  I'm sure this is possible
(and in fact probably easy) but haven't yet seen the light.  Could someone
illuminate me here?
>
> 2) I will be wanting to process strings as lists of strings.  For instance,
I might instead want to send factors above as "x1  x2  x3" and add the
"+" when I need them, or perhaps "*" instead, and also look
at sub-models by removing parts of the string etc.  What functions should I be
looking at here and are there any examples available?
>
> Thanks in advance.  Feel free to CC me on your reply.
>
>
> Michael Hopkins
> Algorithm and Statistical Modelling Expert
>
> Upstream
> 23 Old Bond Street
> London
> W1S 4PZ
>
> Mob +44 0782 578 7220
> DL   +44 0207 290 1326
> Fax  +44 0207 290 1321
>
> hopkins at upstreamsystems.com
> www.upstreamsystems.com
>
> IMPORTANT NOTICE
> The information in this e-mail and any attached files is...{{dropped:22}}
>
> ______________________________________________
> R-help at r-project.org mailing list
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> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
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>