KMeans聚类后的聚类点（scikit learn）

Question

我已经使用 sklearn 使用 Kmeans 完成了聚类。虽然它有一种打印质心的方法，但我发现 scikit-learn 没有一种方法可以打印出每个集群的集群点（或者我到目前为止还没有看到它），这很奇怪。有没有一种巧妙的方法来获取每个集群的集群点？

我目前使用这个相当笨拙的代码来执行此操作，其中 V 是数据集：

def getClusterPoints(V, labels):
    clusters = {}
    for l in range(0, max(labels)+1):
        data_points = []
        indices = [i for i, x in enumerate(labels) if x == l]
        for idx in indices:
            data_points.append(V[idx])
        clusters[l] = data_points
    return clusters

Suggestions/links 非常感谢。

谢谢！ PD.

Answer 1

如果您阅读 documentation，您会发现 kmeans 具有 labels_ 属性。此属性提供集群。

查看下面的完整示例：

import matplotlib.pyplot as plt
from sklearn.cluster import MiniBatchKMeans, KMeans
from sklearn.metrics.pairwise import pairwise_distances_argmin
from sklearn.datasets.samples_generator import make_blobs
import numpy as np

##############################################################################
# Generate sample data
np.random.seed(0)

batch_size = 45
centers = [[1, 1], [-1, -1], [1, -1]]
n_clusters = len(centers)
X, labels_true = make_blobs(n_samples=3000, centers=centers, cluster_std=0.7)

##############################################################################
# Compute clustering with Means

k_means = KMeans(init='k-means++', n_clusters=3, n_init=10)
k_means.fit(X)

##############################################################################
# Plot the results
for i in set(k_means.labels_):
    index = k_means.labels_ == i
    plt.plot(X[index,0], X[index,1], 'o')
plt.show()

Answer 2

例如

import numpy as np
from sklearn.cluster import KMeans
from sklearn import datasets

iris = datasets.load_iris()
X = iris.data
y = iris.target

estimator = KMeans(n_clusters=3)
estimator.fit(X)

你可以通过

得到每个点的聚类

estimator.labels_

输出：

array([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
   0, 0, 0, 0, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
   1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
   1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1, 1,
   2, 2, 2, 2, 1, 2, 1, 2, 1, 2, 2, 1, 1, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2,
   1, 2, 2, 2, 1, 2, 2, 2, 1, 2, 2, 1], dtype=int32)

然后获取每个簇的点索引

{i: np.where(estimator.labels_ == i)[0] for i in range(estimator.n_clusters)}

输出：

{0: array([ 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16,
        17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33,
        34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49]),
 1: array([ 50,  51,  53,  54,  55,  56,  57,  58,  59,  60,  61,  62,  63,
         64,  65,  66,  67,  68,  69,  70,  71,  72,  73,  74,  75,  76,
         78,  79,  80,  81,  82,  83,  84,  85,  86,  87,  88,  89,  90,
         91,  92,  93,  94,  95,  96,  97,  98,  99, 101, 106, 113, 114,
        119, 121, 123, 126, 127, 133, 138, 142, 146, 149]),
 2: array([ 52,  77, 100, 102, 103, 104, 105, 107, 108, 109, 110, 111, 112,
        115, 116, 117, 118, 120, 122, 124, 125, 128, 129, 130, 131, 132,
        134, 135, 136, 137, 139, 140, 141, 143, 144, 145, 147, 148])}

编辑

如果您想使用 X 中的点数组而不是索引数组作为值：

{i: X[np.where(estimator.labels_ == i)] for i in range(estimator.n_clusters)}

KMeans聚类后的聚类点（scikit learn）

cluster points after KMeans clustering (scikit learn)

python

k-means

scikit-learn