R Paste multiple - r

Question

I am currently taking in multiple command line parameters within my R script such as :
args<-commandArgs(TRUE)
arg1 <- as.numeric(args[1])
arg2 <- as.numeric(args[2])
I am wanting to use these args within my paste string like below. My problem is that I can only figure out how to use 1 of the arguments and not both (arg1, arg2). Instead of "xxx" that I show below in my where clause (i.e. "columnname1 in (xxx)") how do I use the "arg1" command line parameter in place of "xxx"? I've tried a number of different ways and for some reason I can't figure it out. Should I concatenate two different strings to accomplish this or is there an easier way?
SQL<-paste(
"SELECT
*
FROM
table
WHERE
columnname1 in (xxx)
and
columnname2 in ('",arg2,"')",sep = "")
Thanks for your help!

Answer 1

Try:
SQL<-paste(
"SELECT
*
FROM
table
WHERE
columnname1 in ('",arg1,"')
and
columnname2 in ('",arg2,"')",sep = "", collapse="")

Answer 2

You could also use the following helper function that allows named substitutions:
SQL<-strsubst(
"SELECT * FROM table WHERE
columnname1 in ('$(arg1)') and
columnname2 in ('$(arg2)')",
list(arg1=arg1, arg2=arg2)
)
where strsubst is defined as follows:
strsubst <- function (template, map, verbose = getOption("verbose"))
{
pat <- "\\$\\([^\\)]+\\)"
res <- template
map <- unlist(map)
m <- gregexpr(pat, template)
idx <- which(sapply(m, function(x) x[[1]] != -1))
for (i in idx) {
line <- template[[i]]
if (verbose)
cat("input: |", template[[i]], "|\n")
starts <- m[[i]]
ml <- attr(m[[i]], "match.length")
sym <- substring(line, starts + 2, starts + ml - 2)
if (verbose)
cat("sym: |", sym, "|\n")
repl <- map[sym]
idx1 <- is.na(repl)
if (sum(idx1) > 0) {
warning("Don't know how to replace '", paste(sym[idx1],
collapse = "', '"), "'.")
repl[idx1] <- paste("$(", sym[idx1], ")", sep = "")
}
norepl <- substring(line, c(1, starts + ml), c(starts -
1, nchar(line)))
res[[i]] <- paste(norepl, c(repl, ""), sep = "", collapse = "")
if (verbose)
cat("output: |", res[[i]], "|\n")
}
return(res)
}