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  • 机器学习-数据预处理、降维、特征提取及聚类

    一、K均值聚类算法

    import numpy as np
    import matplotlib.pyplot as plt
    from sklearn.datasets import make_blobs
    from sklearn.cluster import KMeans
    from sklearn.preprocessing import StandardScaler

    X_1 = StandardScaler().fit_transform(X)
    X, y = make_blobs(n_samples=40, centers=3, random_state=50, cluster_std=2)
    blobs = make_blobs(random_state=1,centers=1)
    X_blobs = blobs[0]
    kmeans = KMeans(n_clusters=3)
    kmeans.fit(X_blobs)

    x_min, x_max = X_blobs[:, 0].min()-0.5 , X_blobs[:, 0].max()+0.5
    y_min, y_max = X_blobs[:, 0].min()-0.5 , X_blobs[:, 1].max()+0.5
    xx, yy = np.meshgrid(np.arange(x_min, x_max, .02),
    np.arange(y_min, y_max, .02))
    Z = kmeans.predict(np.c_[xx.ravel(), yy.ravel()])
    Z = Z.reshape(xx.shape)
    plt.figure(1)
    plt.clf()
    plt.imshow(Z, interpolation='nearest',
    extent=(xx.min(), xx.max(), yy.min(), yy.max()),
    cmap=plt.cm.summer,
    aspect='auto', origin='lower')
    plt.plot(X_blobs[:, 0], X_blobs[:, 1], 'r.', markersize=5)
    centroids = kmeans.cluster_centers_
    plt.scatter(centroids[:, 0], centroids[:, 1],
    marker='x', s=150, linewidths=3,
    color='b', zorder=10)
    plt.xlim(x_min, x_max)
    plt.ylim(y_min, y_max)
    plt.xticks(())
    plt.yticks(())
    plt.show()

    二、凝聚聚类算法工作原理展示

    from scipy.cluster.hierarchy import dendrogram, ward

    linkage = ward(X_blobs)
    dendrogram(linkage)
    ax = plt.gca()
    plt.show()

    三、DBSCAN算法对make_blobs数据集的聚类结果

    from sklearn.cluster import DBSCAN

    db = DBSCAN(min_samples = 20)
    clusters = db.fit_predict(X_blobs)
    plt.scatter(X_blobs[:, 0], X_blobs[:, 1], c=clusters, cmap=plt.cm.cool,
    s=60,edgecolor='k')
    plt.xlabel("Feature 0")
    plt.ylabel("Feature 1")
    plt.show()

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  • 原文地址:https://www.cnblogs.com/zhaop8078/p/9747059.html
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