r - Can you pass a vector to a vararg?: Vector to sprintf

Question

Let's say I have a function that takes variable arguments, such as sprintf(). I want something like:

sprintf("%s %s", "a", "b")

but I have "a" and "b" in a vector c("a", "b"). A call such as

sprintf("%s %s", c("a", "b"))

will produce an error for not enough arguments. Many languages provide a way to "flatten" a vector into a variable-length argument. But I cannot seem to find the syntax for doing so in R. Is there a way?

Answer 1

You can use do.call:

vec <- c("a","b")
do.call(sprintf, c(list("%s %s"), vec))
# [1] "a b"