import SAS ASCII file into R with SAS INPUT text file

import SAS ASCII file into R with SAS INPUT text file

##select file containing SAS input procedure
SASinput <- readLines(file.choose())

##find the first INPUT line
firstline<-min(grep("INPUT @1",toupper(SASinput))) 

##find the first semicolon ending that input line
a<-grep(";",toupper(SASinput)) 
lastline<-min(a[a>firstline])

##isolate the Fixed-Width File input lines
FWFlines<-SASinput[firstline:lastline] 

##break apart all FWF lines 
z<-strsplit(FWFlines," ",perl=T) 
lengths<-grep 

##create FWF structure file (x) 
x<-NULL 

for (i in 1:length(z)){ 
	y<-z[[i]] 
	y<-y[! y %in% c("","INPUT",";")] 
	y<-t(as.data.frame(y)) 
	colnames(y)<-c("placement","varname","format") 
	x<-rbind(x,y) 
} 

x<-data.frame(x) 
x$placement<-as.numeric(sub("\\@","",x$placement)) 

##determine exact width of each variable 
x$width<-as.numeric(substr(x$format , ifelse(grepl("\\$",x$format),2,1) , regexpr("\\.",x$format)-1)) 

##determine number of decimals each variable should have 
x$decimals<-as.numeric(substr(x$format , regexpr("\\.",x$format)+1,length(x$format))) 

##determine whether character or string 
x$charvar<-grepl("\\$",x$format) 

##input actual SAS data text-delimited file to read in 
SASfile <- read.fwf(file.choose() , x$width , col.names=x$varname) 

##convert character strings appropriately within data frame 

for (i in 1:length(x)){ 
	if (x[i,"charvar"]) SASfile[,i]<-as.character(SASfile[,i]) 
	else SASfile[,i]<-as.numeric(SASfile[,i]) 
}

##display final R data frame 
head(SASfile)
tail(SASfile)