Python中的示例K折交叉验证

Question

我想在Python中测试k倍（k = 3）交叉验证

我从网上得到了这段代码

import nltk # needed for Naive-Bayes
import numpy as np
from sklearn.model_selection import KFold

# data is an array with our already pre-processed dataset examples
kf = KFold(n_splits=3)
sum = 0
for train, test in kf.split(data):
    train_data = np.array(data)[train]
    test_data = np.array(data)[test]
    classifier = nltk.NaiveBayesClassifier.train(train_data)
    sum += nltk.classify.accuracy(classifier, test_data)
average = sum/3

并添加：

data = [10, 20, 30, 40, 50]

错误结果：

Traceback (most recent call last):
  File "/Users/david/PycharmProjects/iranian-01/pandas_test.py", line 12, in <module>
classifier = nltk.NaiveBayesClassifier.train(train_data)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/nltk/classify/naivebayes.py", line 194, in train
for featureset, label in labeled_featuresets:
TypeError: 'numpy.int64' object is not iterable

请帮我解决这个问题

Answer 1

在培训和测试之前，您应该先调整数据。 即您将对这些数据进行三重交叉验证

data = [10, 20, 30, 40, 50]

因此，结果将是编译器拆分时的浮点数。 我建议您使用numpy而不是Python纯数组，以便能够使用此库中的预定义函数。