Python style formatting of strings

pymat.R

pymat <- function(string, ...) {
  i <- 0
  for( arg in list(...) ) {
    to_replace <- paste( sep='', "\\{", i, "\\}" )
    string <- gsub( to_replace, arg, string )
    i <- i + 1
  }
  return( string )
}

x <- "Mark"
y <- "Banana"
pymat("This is {0}'s {1}.", x, y)

Thanks for this, I'll be using it to simplify some SQL statements in the morning!