小编Med*_*ata的帖子

我试图了解如何使用交叉验证功能sklearn.model_selection.KFold。如果我定义（就像在本教程中一样）

from sklearn.model_selection import KFold

kf = KFold(n_splits=5, shuffle=False, random_state=100)

我明白了

ValueError: Setting a random_state has no effect since shuffle is False.
You should leave random_state to its default (None), or set shuffle=True. 

这个错误是什么意思以及为什么需要设置random_state=Noneor shuffle=True？

我正在尝试使用以下方法生成和绘制随机数：

from numpy import random
import matplotlib.pyplot as plt

z = 15 + 2*random.randn(200) #200 elements, normal dist with mean = 15, sd = 2

plt.plot(z)
plt.show(z)

该图已绘制，但 Python (2.7.5) 冻结并且出现错误

Traceback (most recent call last):
  File "G:\Stage 2 expt\e298\q1.py", line 25, in <module>
    plt.show(z)
  File "C:\Python27\lib\site-packages\matplotlib\pyplot.py", line 145, in show
    _show(*args, **kw)
  File "C:\Python27\lib\site-packages\matplotlib\backend_bases.py", line 90, in     __call__
    if block:
ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

当我像这样执行 …

我有一系列 numpy 数组，我想将它们保存在 .mat 文件中，以便稍后绘制数据。（我不想使用 Pickle，因为我的实际程序要复杂得多，并且有 2 个以上的数组。）我的 MWE 是：

import numpy as np
import mat4py as m4p

x = np.array([1,20,0.4,0.5,9,8.8])
y = np.array([0.3,0.6,1,1,0.01,0.7])

data = {'x': x,
        'y': y}
m4p.savemat('datafile.mat', data)

但我收到一个错误ValueError: Only dicts, two dimensional numeric, and char arrays are currently supported。

这是什么意思，我该如何解决？

我正在尝试将一段Matlab代码转换为Python并遇到问题.

t = linspace(0,1,256);
s = sin(2*pi*(2*t+5*t.^2));
h = conj(s(length(s):-1:1));

以上行h是为了计算脉冲响应,但是我的Python代码:

import numpy as np

t = np.linspace(0,1,256)
s = np.sin(2*np.pi*(2*t+5*t**2))

h = np.conj(s[len(s),-1,1])

给了我一个错误IndexError: index 256 is out of bounds for axis 0 with size 256.我知道这与索引s数组有关,但我该如何解决呢？