如何在 Python 中制作用于聚类的散点图
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How to make a scatter plot for clustering in Python
提问by Zelong
I am carrying out clustering and try to plot the result. A dummy data set is :
我正在执行聚类并尝试绘制结果。一个虚拟数据集是：
data
数据
import numpy as np
X = np.random.randn(10)
Y = np.random.randn(10)
Cluster = np.array([0, 1, 1, 1, 3, 2, 2, 3, 0, 2]) # Labels of cluster 0 to 3
cluster center
集群中心
centers = np.random.randn(4, 2) # 4 centers, each center is a 2D point
Question
题
I want to make a scatter plot to show the points in dataand color the points based on the cluster labels.
我想制作一个散点图来显示点data并根据集群标签为点着色。
Then I want to superimpose the centerpoints on the same scatter plot, in another shape (e.g. 'X') and a fifth color (as there are 4 clusters).
然后我想将center点叠加在同一个散点图上，以另一种形状（例如“X”）和第五种颜色（因为有 4 个簇）。
Comment
评论
- I turned to seaborn0.6.0 but found no API to accomplish the task.
- ggplotby yhat could made the scatter plot nice but the second plot would replace the first one.
- I got confused by the
colorandcmapin matplotlibso I wonder if I could use seaborn or ggplot to do it.
- 我转向了seaborn0.6.0，但发现没有 API 来完成任务。
- yhat的 ggplot 可以使散点图很好，但第二个图将替换第一个图。
- 我对matplotlib 中的
colorand感到困惑，所以我想知道我是否可以使用 seaborn 或 ggplot 来做到这一点。cmap
采纳答案by ThePredator
The first part of your question can be done using colorbarand specifying the colours to be the Clusterarray. I have vaguely understood the second part of your question, but I believe this is what you are looking for.
问题的第一部分可以使用colorbar并指定要作为Cluster数组的颜色来完成。我对你问题的第二部分有模糊的理解，但我相信这就是你要找的。
import numpy as np
import matplotlib.pyplot as plt
x = np.random.randn(10)
y = np.random.randn(10)
Cluster = np.array([0, 1, 1, 1, 3, 2, 2, 3, 0, 2]) # Labels of cluster 0 to 3
centers = np.random.randn(4, 2)
fig = plt.figure()
ax = fig.add_subplot(111)
scatter = ax.scatter(x,y,c=Cluster,s=50)
for i,j in centers:
ax.scatter(i,j,s=50,c='red',marker='+')
ax.set_xlabel('x')
ax.set_ylabel('y')
plt.colorbar(scatter)
fig.show()
which results in:
这导致：
wherein your "centres" have been shown using +marker. You can specify any colours you want to them in the same way have done for x and y
其中您的“中心”已使用+标记显示。您可以使用相同的方式为它们指定您想要的任何颜色x and y
回答by jotrocken
Part of this has been answered here. The outline is
部分问题已在此处得到解答。大纲是
plt.scatter(x, y, c=color)
Quoting the documentation of matplotlib:
引用matplotlib的文档：
c : color or sequence of color, optional, default [...] Note that c should not be a single numeric RGB or RGBA sequence because that is indistinguishable from an array of values to be colormapped. c can be a 2-D array in which the rows are RGB or RGBA, however.
c ：颜色或颜色序列，可选，默认 [...] 请注意，c 不应是单个数字 RGB 或 RGBA 序列，因为它与要进行颜色映射的值数组无法区分。然而，c 可以是一个二维数组，其中的行是 RGB 或 RGBA。
So in your case, you need a color for each cluster and than fill the color array according to the cluster assignment of each point.
因此，在您的情况下，您需要为每个集群设置一种颜色，然后根据每个点的集群分配填充颜色数组。
red = [1, 0, 0]
green = [0, 1, 0]
blue = [0, 0, 1]
colors = [red, red, green, blue, green]
