基本上,我希望绘制出这样的图表:
我已经成功地使用以下代码绘制了聚类图:
sns.scatterplot(X[:,0], X[:,1], hue=y, palette=['red', 'blue', 'purple', 'green'], alpha=0.5, s=7)
结果如下:
如何像前面的图片一样标记出中心点呢?
回答:
你可以计算每个组的平均值,并在该位置绘制一个散点图点。
from matplotlib import pyplot as pltimport seaborn as snsimport numpy as npN = 1000X0 = np.random.normal(np.repeat(np.random.uniform(0, 20, 4), N), 1)X1 = np.random.normal(np.repeat(np.random.uniform(0, 10, 4), N), 1)X = np.vstack([X0, X1]).Ty = np.repeat(range(4), N)colors = ['red', 'blue', 'purple', 'green']ax = sns.scatterplot(X[:, 0], X[:, 1], hue=y, palette=colors, alpha=0.5, s=7)means = np.vstack([X[y == i].mean(axis=0) for i in range(4)])ax = sns.scatterplot(means[:, 0], means[:, 1], hue=range(4), palette=colors, s=20, ec='black', legend=False, ax=ax)plt.show()
或者,可以使用Scikit Learn的KMeans
来计算KMeans标签和中心点:
from sklearn.cluster import KMeansfrom matplotlib import pyplot as pltimport numpy as npimport seaborn as snsN = 500X0 = np.random.normal(np.repeat(np.random.uniform(0, 20, 20), N), 3)X1 = np.random.normal(np.repeat(np.random.uniform(0, 10, 20), N), 2)X = np.vstack([X0, X1]).Tnum_clusters = 4kmeans = KMeans(n_clusters=num_clusters).fit(X)colors = ['red', 'blue', 'purple', 'green']ax = sns.scatterplot(X[:, 0], X[:, 1], hue=kmeans.labels_, palette=colors, alpha=0.5, s=7)ax = sns.scatterplot(kmeans.cluster_centers_[:, 0], kmeans.cluster_centers_[:, 1], hue=range(num_clusters), palette=colors, s=20, ec='black', legend=False, ax=ax)plt.show()