C5.0 decision tree - c50 code called exit with value 1

Question

I am getting the following error

c50 code called exit with value 1

I am doing this on the titanic data available from Kaggle

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Answer 1

I also struggled some hours with the same Problem (Return code "1") when building a model as well as when predicting. With the hint of answer of Marco I have written a small function to remove all factor levels equal to "" in a data frame or vector, see code below. However, since R does not allow for pass by reference to functions, you have to use the result of the function (it can not change the original dataframe):

removeBlankLevelsInDataFrame <- function(dataframe) {
  for (i in 1:ncol(dataframe)) {
    levels <- levels(dataframe[, i])
    if (!is.null(levels) && levels[1] == "") {
      levels(dataframe[,i])[1] = "?"
    }
  }
  dataframe
}

removeBlankLevelsInVector <- function(vector) {
  levels <- levels(vector)
  if (!is.null(levels) && levels[1] == "") {
    levels(vector)[1] = "?"
  }
  vector
}

Call of the functions may look like this:

trainX = removeBlankLevelsInDataFrame(trainX)
trainY = removeBlankLevelsInVector(trainY)
model = C50::C5.0.default(trainX,trainY)

However, it seems, that C50 has a similar Problem with character columns containing an empty cell, so you will have probably to extend this to handle also character attributes if you have some.