x <-  seq(-2,2,by = 0.1)
if(x <= 0){
  y <- -x^3
  }else if(x <= 1){
    y <- x^2
    }else{
      y <- sqrt(x)
      }
show(y)

出现问题
Warning message:
In if (x <= 0) { :
  the condition has length > 1 and only the first element will be used
应该怎么改？
急急急！！！