通过R方式将不同函数的结果传递给函数

Question

I have multiple functions and want to pass their results to another function (multiple function calls). What is the R-way of doing this?

Ex.

x = function_x() { ... return vector}
y = function_y() { ... return vector}
z = function_z() { ... return vector}
func_abc(x)
func_abc(y)
func_abc(z)

Currently I am creating a vector of functions and using lapply to pass their results on multiple function calls:

function_x() { ... return vector}
function_y() { ... return vector}
function_z() { ... return vector}

my_vectors <- c(function_x(), function_y(), function_z())

lapply(my_vectors, function_abc(v) {
  ... do something on v
})

To be more specific, function_x, _y, and _z returns vectors. I want to do some filtering for their returned vectors which is my function_abc. Then combine them.

Answer 1

Try this example:

#set seed to make it reproducible
set.seed(1234)

#define functions
function_x <- function(){ sample(1) }
function_y <- function(){ sample(2) }
function_z <- function(){ sample(3) }

#get function results into a list
myList <- list(function_x(), function_y(), function_z())

#loop through the list and row bind
do.call(rbind,
  lapply(myList, function(v) {
    #some calculations, result is a data.frame
    res <- cbind.data.frame(input=v, calculation=v*2)
    return(res)
  }))

#result
#  input calculation
#1     1           2
#2     2           4
#3     1           2
#4     2           4
#5     3           6
#6     1           2

Above can be simplified as below:

#define function for calculations
function_abc <- function(x){ x * 2 }

#loop
unlist(lapply(list(function_x(), function_y(), function_z()), function_abc))

#result
# [1] 2 4 2 4 6 2