title: Identifying positivity and negativity separately from a negative dataset
body: <p>First of all, i would like you to know that I am new to machine learning (ML). I am working on a project which detects how <strong>positive or negative</strong> a set of words can be, therefore i have created a database containing possible <strong>negative</strong> words. So that ML can take place and predict the overall score on how <strong>positive or negative</strong> the whole set of words. 
  My questions are is it possible to classify <strong>positive</strong> words with only  <strong>negative</strong> words in the dataset? Does it affect the accuracy of predicting if it is possible?</p>