I am trying to develop a classification model. This is to predict that the given task will be completed in the given time or not. When I have gone through the data there are many null values and the task is also contains different phases. So I am trying to develop a predictive model depends on the features availability . For example I the the task has 3 features the model should be run with 3 features only, if it has 5 features it should be run with 5 features. Please let me know that how we can achieve it and of there is any sample code that will be appreciated.