Bayesian Learning

import sys

def load_features(train_f):
    features = {}
    feature_for_index = {}
    index = 0
    for feature in train_f.readline().replace('\n', '').split('\t'):
        features[feature] = []
        feature_for_index[index] = feature
        index += 1

    for line in train_f:
        split = line.replace('\n', '').split('\t')
        for i in range(len(split)):
            features[feature_for_index[i]].append(int(split[i]))

    return features

def frequency_table(values):
    unique_value_count = {}
    for value in values:
        if value not in unique_value_count:
            unique_value_count[value] = 1
        else:
            unique_value_count[value] += 1
    return unique_value_count

def filter_feature_for_class(features, clazz, feature):
    filtered_values = []
    for i in range(len(features['class'])):
        if features['class'][i] == clazz:
            filtered_values.append(features[feature][i])
    return filtered_values

def print_learning(features):
    class_freq_table = frequency_table(features['class'])
    total = sum(class_freq_table.values())
    for clazz in sorted(class_freq_table.keys()):
        class_total = class_freq_table[clazz]
        class_p = class_total / total
        print('P(class=' + str(clazz) + ')=%.2f ' % class_p, end='')

        for feature in features.keys():
            if feature == 'class':
                continue
            values_for_feature = filter_feature_for_class(features, clazz, feature)
            feature_freq_table = frequency_table(values_for_feature)

            for feature_value in sorted(feature_freq_table.keys()):
                count = feature_freq_table[feature_value]
                feature_value_p = count / class_total
                print('P(' + feature + '=' + str(feature_value) + '|' + str(clazz) + ')=%.2f ' % feature_value_p, end='')

        print()

if len(sys.argv) != 3:
    print('You must specify only a training data file and test data file in the program parameters; nothing more or less.')
else:
    train_file = sys.argv[1]
    test_file = sys.argv[2]

    train_f = open(train_file, 'r')
    features = load_features(train_f)

    print_learning(features)