[R] how Can make function for selecting the products

[Jessica Streicher]

If i understand this correctly, what you want to use is a vector or a list as a parameter to that function.

getdata<-function(letterVec){
	...
	query<-paste("SELECT *FROM myfile1 where MODEL in", sqlListFromVector(letterVec))      
	...
}

sqlListFromVector<-function(v){
	if(is.numeric(v)){
		help<-paste(v,sep="",collapse=",")
	}
	else{
		help<-paste("'",v,"'",sep="",collapse=",")
	}
	result<-paste("(",help,")",sep="")
	return(result)
}

Then you can put any character or number in letterVec, e.g.

letterVec<-c("a","b","c")
getdata(letterVec)

does that help?

On 06.11.2012, at 13:13, Tammy Ma wrote:

> 
> HI.
> 
> I make this code:
> 
> getdata<-function('a','b','c' ,'d','e','f'){
> 
> drv <- dbDriver("SQLite")
> con<-dbConnect(drv, "sqlite.db")
> 
> lt<-dbListTables(con)
> 
> myf<-data.frame(NULL)
> 
> for (i in 1:length(lt))
> 
> {
> myfile<-dbReadTable(con,lt[i])
> myfile1<-myfile[-c(14:44)]
> myfile1$MODEL<-gsub(" ", "", myfile1$MODEL)
> library(RSQLite)
> library(sqldf)
> my_file<-sqldf("SELECT *
>       FROM myfile1 where MODEL in ('a','b','c' ,'d','e','f')")
> my.file.spes<-conv(my_file)
> myf<-rbind(myf,my.file.spes)
> 
> }
> wd<-myf[order(myf$Product, myf$Time),]
> wd1<-wd[!duplicated(wd),]
> wd2<-as.data.frame(as.matrix(wd1),stringsAsFactors = FALSE)
> wd3<-transform(wd2, Price = as.numeric(Price),
>               Volume = as.numeric(Volume))
> 
> dbDisconnect(con)
> 
> return(wd3)
> 
> }
> 
> 
> I want this program also work when I use 
> 
> wd3<-getdata(a,b,c,d,e,f,g,h...)
> 
> for any length of my selection. How should I do this then?
> 
> 
> Thanks-
> 
> 
> Tammy
> 
> 
> 		 	   		  
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> 
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