在R中具有数组输入的if-else语句

Question

I want to write a custom threshold function like that:

doubleThres <- function(value)
{
  if(value >=0.8)
  {
    value = value * 0.8

  }

  if( value < 0.5)
  {
    value = max(value * 1.2, value + 0.1)
  }
  return(value)
}

If I input one single value like 1.2, then the function works fine. However, I want to input an array, which was one column of the data frame.

doubleThres(myDataFrame$value)

Then it would report error.

In if (vale >= 0.8) { :
  the condition has length > 1 and only the first element will be used

I know the function has problem, but I don't know how to correct it in a simple way, without using for-loop in the function.

Answer 1

There were already suggestions in the comments that would work, but if you want to keep the structure of your function you can use logical indexing:

doubleThres <- function(value)
{
    value[value >= 0.8] <- value[value >= 0.8] * 0.8
    value[value < 0.5] <- pmax(value[value < 0.5] * 1.2, value[value < 0.5] + 0.1)
    return(value)
}