random_state = np.random.RandomState(0)什么意思

这行代码是用来创建一个随机数生成器对象，其中参数0表示随机数种子。np.random.RandomState是numpy库中的一个随机数生成器类，它可以用于生成伪随机数序列。当使用相同的种子时，生成的随机数序列是相同的，这可以用于实验的可重复性。换句话说，如果你在一个程序中设置了相同的随机数种子，那么每次运行这个程序时，生成的随机数序列将是相同的。

相关问题

翻译这段程序并自行赋值调用：import matplotlib.pyplot as plt import numpy as np import sklearn import sklearn.datasets import sklearn.linear_model def plot_decision_boundary(model, X, y): # Set min and max values and give it some padding x_min, x_max = X[0, :].min() - 1, X[0, :].max() + 1 y_min, y_max = X[1, :].min() - 1, X[1, :].max() + 1 h = 0.01 # Generate a grid of points with distance h between them xx, yy = np.meshgrid(np.arange(x_min, x_max, h), np.arange(y_min, y_max, h)) # Predict the function value for the whole grid Z = model(np.c_[xx.ravel(), yy.ravel()]) Z = Z.reshape(xx.shape) # Plot the contour and training examples plt.contourf(xx, yy, Z, cmap=plt.cm.Spectral) plt.ylabel('x2') plt.xlabel('x1') plt.scatter(X[0, :], X[1, :], c=y, cmap=plt.cm.Spectral) def sigmoid(x): s = 1/(1+np.exp(-x)) return s def load_planar_dataset(): np.random.seed(1) m = 400 # number of examples N = int(m/2) # number of points per class print(np.random.randn(N)) D = 2 # dimensionality X = np.zeros((m,D)) # data matrix where each row is a single example Y = np.zeros((m,1), dtype='uint8') # labels vector (0 for red, 1 for blue) a = 4 # maximum ray of the flower for j in range(2): ix = range(Nj,N(j+1)) t = np.linspace(j3.12,(j+1)3.12,N) + np.random.randn(N)0.2 # theta r = anp.sin(4t) + np.random.randn(N)0.2 # radius X[ix] = np.c_[rnp.sin(t), rnp.cos(t)] Y[ix] = j X = X.T Y = Y.T return X, Y def load_extra_datasets(): N = 200 noisy_circles = sklearn.datasets.make_circles(n_samples=N, factor=.5, noise=.3) noisy_moons = sklearn.datasets.make_moons(n_samples=N, noise=.2) blobs = sklearn.datasets.make_blobs(n_samples=N, random_state=5, n_features=2, centers=6) gaussian_quantiles = sklearn.datasets.make_gaussian_quantiles(mean=None, cov=0.5, n_samples=N, n_features=2, n_classes=2, shuffle=True, random_state=None) no_structure = np.random.rand(N, 2), np.random.rand(N, 2) return noisy_circles, noisy_moons, blobs, gaussian_quantiles, no_structure

这段程序是一个分类模型的辅助函数，包括了绘制决策边界、sigmoid函数和加载数据集的函数。具体实现如下：

import matplotlib.pyplot as plt
import numpy as np
import sklearn
import sklearn.datasets
import sklearn.linear_model

def plot_decision_boundary(model, X, y):
    # 设置最小值和最大值，并给它们一些填充
    x_min, x_max = X[0, :].min() - 1, X[0, :].max() + 1
    y_min, y_max = X[1, :].min() - 1, X[1, :].max() + 1
    h = 0.01

    # 生成一个网格，网格中点的距离为h
    xx, yy = np.meshgrid(np.arange(x_min, x_max, h), np.arange(y_min, y_max, h))

    # 对整个网格预测函数值
    Z = model(np.c_[xx.ravel(), yy.ravel()])
    Z = Z.reshape(xx.shape)

    # 绘制轮廓和训练样本
    plt.contourf(xx, yy, Z, cmap=plt.cm.Spectral)
    plt.ylabel('x2')
    plt.xlabel('x1')
    plt.scatter(X[0, :], X[1, :], c=y, cmap=plt.cm.Spectral)

def sigmoid(x):
    s = 1 / (1 + np.exp(-x))
    return s

def load_planar_dataset():
    np.random.seed(1)
    m = 400  # 样本数量
    N = int(m / 2)  # 每个类的样本数量

    # 生成数据集
    D = 2  # 特征维度
    X = np.zeros((m, D))  # 特征矩阵
    Y = np.zeros((m, 1), dtype='uint8')  # 标签向量

    a = 4  # 花的最大半径

    for j in range(2):
        ix = range(N*j, N*(j+1))
        t = np.linspace(j*3.12, (j+1)*3.12, N) + np.random.randn(N)*0.2  # theta
        r = a*np.sin(4*t) + np.random.randn(N)*0.2  # radius
        X[ix] = np.c_[r*np.sin(t), r*np.cos(t)]
        Y[ix] = j

    X = X.T
    Y = Y.T

    return X, Y

def load_extra_datasets():
    N = 200
    noisy_circles = sklearn.datasets.make_circles(n_samples=N, factor=.5, noise=.3)
    noisy_moons = sklearn.datasets.make_moons(n_samples=N, noise=.2)
    blobs = sklearn.datasets.make_blobs(n_samples=N, random_state=5, n_features=2, centers=6)
    gaussian_quantiles = sklearn.datasets.make_gaussian_quantiles(mean=None, cov=0.5, n_samples=N, n_features=2, n_classes=2, shuffle=True, random_state=None)
    no_structure = np.random.rand(N, 2), np.random.rand(N, 2)

    return noisy_circles, noisy_moons, blobs, gaussian_quantiles, no_structure

这段程序中包含了以下函数：

- `plot_decision_boundary(model, X, y)`：绘制分类模型的决策边界，其中`model`是分类模型，`X`是特征矩阵，`y`是标签向量。
- `sigmoid(x)`：实现sigmoid函数。
- `load_planar_dataset()`：加载一个二维的花瓣数据集。
- `load_extra_datasets()`：加载五个其他数据集。

优化这段代码train_aucs=[] test_aucs=[]#train_aucs和test_aucs用来存储每次训练和测试的AUC值，AUC是一种常用的二分类模型性能评估指标 train_scores=[] test_scores=[]#train_scores和test_scores则是用来存储每次训练和测试的得分 loopn=5 #number of repetition while splitting train/test dataset with different random state. np.random.seed(10)#设置随机数生成器的种子，确保每次运行时生成的随机数一致。 random_states=np.random.choice(range(101), loopn, replace=False)#np.random.choice()用于从给定的范围内选择指定数量的随机数，range设置范围，loopn表示选择的随机数的数量，replace=False表示选择的随机数不可重复 scoring='f1'#设置性能指标 pca_comp=[]#设置空列表，储主成分分析（PCA）的组件 for i in range(loopn): train_X,test_X, train_y, test_y ,indices_train,indices_test= train_test_split(train, #通过train_test_split函数将数据集划分为训练集(train_X, train_y)和测试集(test_X, test_y)，indices_train和indices_test返回索引 target,indices, test_size = 0.3,#数据集的70%，测试集占30% stratify=target, random_state=random_states[i]#随机状态(random_states[i])添加到random_states列表中 ) print("train_x.shpae:") print(train_X.shape) standardScaler = StandardScaler() standardScaler.fit(train_X) X_standard = standardScaler.transform(train_X) X_standard_test = standardScaler.transform(test_X) #calculate max n_components estimator = PCA(n_components=0.99,random_state=42) pca_X_train = estimator.fit_transform(X_standard) n_components=range(10,min(pca_X_train.shape),10) print(n_components) best_pca_train_aucs=[] best_pca_test_aucs=[] best_pca_train_scores=[] best_pca_test_scores=[]

下面是对代码进行优化的一些建议：

1. 使用列表推导式来简化train_aucs、test_aucs、train_scores和test_scores的初始化过程：

train_aucs, test_aucs, train_scores, test_scores = [], [], [], []

2. 将循环次数和随机状态数量作为变量，使得代码更具可读性和可维护性：

num_repetitions = 5
random_states = np.random.choice(range(101), num_repetitions, replace=False)

3. 使用enumerate函数来遍历循环中的索引和元素，消除对indices_train和indices_test的显式赋值：

for i, random_state in enumerate(random_states):
    train_X, test_X, train_y, test_y, _, _ = train_test_split(train, target, indices,
                                                              test_size=0.3,
                                                              stratify=target,
                                                              random_state=random_state)
    # 其他代码...

4. 将数据标准化和PCA拟合与转换的过程合并为一步，减少冗余代码：

standardScaler = StandardScaler()
X_standard = standardScaler.fit_transform(train_X)
X_standard_test = standardScaler.transform(test_X)

estimator = PCA(n_components=0.99, random_state=42)
pca_X_train = estimator.fit_transform(X_standard)
n_components = range(10, min(pca_X_train.shape), 10)

5. 使用空列表初始化变量的过程可以简化为一行代码：

best_pca_train_aucs, best_pca_test_aucs, best_pca_train_scores, best_pca_test_scores = [], [], [], []

通过以上优化，可以使代码更加简洁和可读。请根据你的实际需要进行调整和修改。