Function to apply arbitrary functions in R

How would one implement in R the function apply.func(func, arg.list), which takes an arbitrary function func and a suitable list arg.list as arguments, and returns the result of calling func with the argum开发者_开发百科ents contained in arg.list. E.g.

apply.func(foo, list(x="A", y=1, z=TRUE))

is equivalent to

foo(x="A", y=1, z=TRUE)

Thanks!

P.S. FWIW, the Python equivalent of apply.func would be something like

def apply_func(func, arg_list):
    return func(*arg_list)

or

def apply_func(func, kwarg_dict):
    return func(**kwarg_dict)

or some variant thereof.

I think do.call is what you're looking for. You can read about it via ?do.call.

The classic example of how folks use do.call is to rbind data frames or matrices together:

d1 <- data.frame(x = 1:5,y = letters[1:5])
d2 <- data.frame(x = 6:10,y = letters[6:10])

do.call(rbind,list(d1,d2))

Here's another fairly trivial example using sum:

do.call(sum,list(1:5,runif(10)))

R allows functions to be passed as arguments to functions. This means you can define apply.func as follows (where f is a function and ... indicates all other parameters:

apply.func <- function(f, ...)f(...)

You can then use apply.func to and specify any function where the parameters makes sense:

apply.func(paste, 1, 2, 3)
[1] "1 2 3"

apply.func(sum, 1, 2, 3)
[1] 6

However, note that the following may not produce the results you expected, since mean takes a vector as an argument:

apply.func(mean, 1, 2, 3)
[1] 1

Note that there is also a base R function called do.call which effectively does the same thing.