The order of prediction columns

[pplonski]

In the case of many classes the predictions columns have wrong order:

'prediction_0', 'prediction_1', 'prediction_10', 'prediction_100', 'prediction_101', 'prediction_102', 'prediction_103', 'prediction_104' ...

It should be:

prediction_0, prediction_1, prediction_2, ...

[pplonski]

The error was because the difference in sorting string vs sorting numbers (even if the string contains a number). The class for multiclass classification is always treated as a string. Thus, we force the LabelEncoder to try to cast it to the number and then sort.