functional programming in R

Question

I have been reading the Functionals from github. One suggestion in the page was to use call_function if one is working with a list of functions. Here is the code from the page:

call_fun <- function(f, ...) f(...)
f <- list(sum, mean, median, sd)
lapply(f, call_fun, x = runif(1e3))

The output was posted as:

# [[1]]
# [1] 498
# 
# [[2]]
# [1] 0.498
# 
# [[3]]
# [1] 0.49
# 
# [[4]]
# [1] 0.29

However, I was not able to replicate the above results. I got the error:

Error in FUN(X[[4L]], ...) : could not find function "f"

Am I missing something here?

Answer 1

You have redefined the function sd:

sd = 2

call_fun <- function(f, ...) f(...)
f <- list(sum, mean, median, sd)
lapply(f, call_fun, x = runif(1e3))
#Error in FUN(X[[4L]], ...) : could not find function "f"

Restart your session or do rm(sd).