Package Bio :: Module NaiveBayes
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Module NaiveBayes

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General Naive Bayes learner.

Naive Bayes is a supervised classification algorithm that uses Bayes rule to compute the fit between a new observation and some previously observed data. The observations are discrete feature vectors, with the Bayes assumption that the features are independent. Although this is hardly ever true, the classifier works well enough in practice.

Glossary:
Classes:
Functions:
Classes [hide private]
  NaiveBayes
Hold information for a NaiveBayes classifier.
Functions [hide private]
 
_contents(items)
Return a dictionary where the key is the item and the value is the probablity associated (PRIVATE).
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calculate(nb, observation, scale=False)
Calculate the logarithmic conditional probability for each class.
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classify(nb, observation)
Classify an observation into a class.
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train(training_set, results, priors=None, typecode=None)
Train a NaiveBayes classifier on a training set.
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Variables [hide private]
  __package__ = 'Bio'
Function Details [hide private]

calculate(nb, observation, scale=False)

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Calculate the logarithmic conditional probability for each class.

Arguments:
  • nb - A NaiveBayes classifier that has been trained.
  • observation - A list representing the observed data.
  • scale - Boolean to indicate whether the probability should be scaled by P(observation). By default, no scaling is done.

A dictionary is returned where the key is the class and the value is the log probability of the class.

train(training_set, results, priors=None, typecode=None)

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Train a NaiveBayes classifier on a training set.

Arguments:
  • training_set - List of observations.
  • results - List of the class assignments for each observation. Thus, training_set and results must be the same length.
  • priors - Optional dictionary specifying the prior probabilities for each type of result. If not specified, the priors will be estimated from the training results.