为什么sk中的k-折叠学习不能打印数组值

Question

我遵循了sklearn k-fold验证的文档，并编写了以下代码：

    import numpy as np
from sklearn.model_selection import KFold

X = ["w", "x", "y", "a"]
print(X[0])
kf = KFold(n_splits=4)
for train, test in kf.split(X):
    print(X[(test)])

它在最后一行输出一个错误：

TypeError: only integer scalar arrays can be converted to a scalar index

为什么会出现这个错误？对不起，显然我是个初学者。

Answer 1

正如错误所说的那样。您的错误来自于print语句。这是因为KFold.split生成的索引与python列表不兼容。尝尝这个,

import numpy as np
from sklearn.model_selection import KFold

X = np.array(["w", "x", "y", "a"])
kf = KFold(n_splits=4)
for train, test in kf.split(X):
    print(train, test)
    print(X[test])

输出：

[1 2 3] [0]
['w']
[0 2 3] [1]
['x']
[0 1 3] [2]
['y']
[0 1 2] [3]
['a']