Python style string formatting in R

format_str.R

example <- "An example {1} where adding {2} and {2} and {3}"

val.1 <- "Value 1"
val.2 <- "Value 2"
val.3 <- "Value 3"

format_str <- function(string, ...) {
    args <- list(...)
    for (i in 1:length(args)) {
        pattern <- paste("\\{", i, "}", sep="")
        replacement <- args[[i]]
        string <- gsub(pattern, replacement, string)
    }
    return(string)
}

print(format_str(example, val.1, val.2, val.3))