R Piecewise Function with Multiple Outputs -

i have 2 functions, each of return 2 values (as list) , operate on limited domain:

# x >= 0 f <- function(x) { return(list(a=x,b=2*x)) } # x < 0 g <- function(x) { return(list(a=x/2,b=x/4)) } 

i want this:

fg <- function(x) { return(ifelse(x < 0, g(x), f(x))) } 

and i'd this:

> fg(c(1,2)) a$ [1] 1 2 b$ [2] 2 4  > fg(c(-1,-2) a$ [1] -0.5 -1.0 b$ [2] -0.25 -0.50 

instead, getting this:

> fg(c(1,2)) [[1]] [1] 1 2  [[2]] [1] 2 4  > fg(c(-1,-2)) [[1]] [1] -0.5 -1.0  [[2]] [1] -0.25 -0.50 

the "$a" , "$b" labels getting lost.

with single input, it's worse:

> fg(1) [[1]] [1] 1 

what doing wrong?

how can achieve objective?

i have modified code,

# x >= 0 f <- function(x) { return(list(a=x,b=2*x)) } # x < 0 g <- function(x) { return(list(a=x/2,b=x/4)) } fg <- function(x) {     tmp <- lapply(x, function(y) switch(as.character(y > 0), 'true' = f(y), 'false' = g(y)))     <- sapply(tmp, function(y) y$a)     b <- sapply(tmp, function(y) y$b)     out <- list(a = a, b = b)     return(out) } 

---

this version, gives results desire not need functions f , g. also, computation vectorised:

fg2 <- function(x) {     list(         = x * (1/2)^(x < 0),          b = x * 2 * (1/8)^(x < 0)     ) } 

below examples,

> fg2(1) $a [1] 1  $b [1] 2  > fg2(1:2) $a [1] 1 2  $b [1] 2 4  > fg2(-2:2) $a [1] -1.0 -0.5  0.0  1.0  2.0  $b [1] -0.50 -0.25  0.00  2.00  4.00