intro2ai/p5_classification/mostFrequent.py

41 lines
1.5 KiB
Python

# mostFrequent.py
# ---------------
# Licensing Information: You are free to use or extend these projects for
# educational purposes provided that (1) you do not distribute or publish
# solutions, (2) you retain this notice, and (3) you provide clear
# attribution to UC Berkeley, including a link to http://ai.berkeley.edu.
#
# Attribution Information: The Pacman AI projects were developed at UC Berkeley.
# The core projects and autograders were primarily created by John DeNero
# (denero@cs.berkeley.edu) and Dan Klein (klein@cs.berkeley.edu).
# Student side autograding was added by Brad Miller, Nick Hay, and
# Pieter Abbeel (pabbeel@cs.berkeley.edu).
import util
import classificationMethod
class MostFrequentClassifier(classificationMethod.ClassificationMethod):
"""
The MostFrequentClassifier is a very simple classifier: for
every test instance presented to it, the classifier returns
the label that was seen most often in the training data.
"""
def __init__(self, legalLabels):
self.guess = None
self.type = "mostfrequent"
def train(self, data, labels, validationData, validationLabels):
"""
Find the most common label in the training data.
"""
counter = util.Counter()
counter.incrementAll(labels, 1)
self.guess = counter.argMax()
def classify(self, testData):
"""
Classify all test data as the most common label.
"""
return [self.guess for i in testData]