Getting "Error in as.vector(x.mode): cannot coerce type 'closure' to vector of type 'any'"

Question

I keep getting the following error.

Error in as.vector(x, mode) : 
  cannot coerce type 'closure' to vector of type 'any'

I want to plot f2(x) versus x using the matplot option in RStudio. Is there something I'm missing?

f2<-function(x){
  if(x>=0){
    return(sqrt(x))
  }else{
    return(sqrt(-x))
  }
}

x<- seq(from= -5, to= 5, by= 0.001)

require(graphics)
matplot(f2, x, type = "1", xlab = expression(alpha), ylab = expression(sqrt(abs(alpha)))) 

Answer 1

The function f2 was not applied on 'x'. Having said that, if/else would not be efficient here as it is not vectorized and we may need to loop if we need to apply. Instead another function with ifelse or within in the function create a logical index and replace the original vector based on the index

f1 <- function(v) {
  i1 <- v >= 0
  v[i1] <- sqrt(v[i1])
  v[!i1] <- sqrt(-v[!i1])
   v
 }
matplot(f1(x), type = "l", xlab = expression(alpha),
              ylab = expression(sqrt(abs(alpha))))