用python实现:对Mall Customers 的200*4数据集提供的信息,其中文件后三列为特征,使用DBSCAN聚类分析
时间: 2024-03-04 19:49:33 浏览: 62
好的,以下是实现代码:
```python
import pandas as pd
from sklearn.cluster import DBSCAN
from sklearn.preprocessing import StandardScaler
# 读取数据
data = pd.read_csv('Mall_Customers.csv', usecols=[2, 3, 4])
# 数据标准化
scaler = StandardScaler()
data_scaled = scaler.fit_transform(data)
# DBSCAN聚类
dbscan = DBSCAN(eps=0.5, min_samples=5)
dbscan.fit(data_scaled)
# 输出聚类结果
print(dbscan.labels_)
```
解释一下代码:
1. 首先,我们使用 Pandas 库读取数据集,只保留后三列特征数据。
2. 然后,我们对数据进行标准化处理,使得每一列数据的均值为0,方差为1。
3. 接着,我们使用 sklearn 库中的 DBSCAN 聚类算法对标准化后的数据进行聚类,设置聚类的参数 eps 和 min_samples。
4. 最后,输出每个数据点所属的聚类类别。
需要注意的是,DBSCAN 算法中的参数 eps 和 min_samples 需要根据实际情况进行调整,以得到最优的聚类效果。
相关问题
使用Python实现DBSCAN聚类分析
DBSCAN是一种基于密度的聚类算法,可以用于发现任意形状的簇。它的核心思想是将密度相连的样本点划分为一个簇,并且可以识别噪声点。下面是使用Python实现DBSCAN聚类分析的步骤:
1. 导入需要的库和数据集
```python
import numpy as np
from sklearn.cluster import DBSCAN
from sklearn.datasets import make_blobs
import matplotlib.pyplot as plt
# 生成样本数据,共1000个点,4个中心点,标准差为0.5
X, y = make_blobs(n_samples=1000, centers=4, cluster_std=0.5, random_state=0)
```
2. 设置DBSCAN参数,并进行聚类分析
```python
dbscan = DBSCAN(eps=0.5, min_samples=5) # eps为邻域半径,min_samples为邻域内最少样本数
dbscan.fit(X)
```
3. 可视化聚类结果
```python
# 可视化结果
plt.scatter(X[:, 0], X[:, 1], c=dbscan.labels_, cmap='rainbow')
plt.title('DBSCAN Clustering')
plt.show()
```
完整代码如下:
```python
import numpy as np
from sklearn.cluster import DBSCAN
from sklearn.datasets import make_blobs
import matplotlib.pyplot as plt
# 生成样本数据,共1000个点,4个中心点,标准差为0.5
X, y = make_blobs(n_samples=1000, centers=4, cluster_std=0.5, random_state=0)
# 设置DBSCAN参数,并进行聚类分析
dbscan = DBSCAN(eps=0.5, min_samples=5) # eps为邻域半径,min_samples为邻域内最少样本数
dbscan.fit(X)
# 可视化结果
plt.scatter(X[:, 0], X[:, 1], c=dbscan.labels_, cmap='rainbow')
plt.title('DBSCAN Clustering')
plt.show()
```
运行代码后,会得到一个可视化的聚类结果图。可以看出,DBSCAN算法成功地将数据集分为了4个簇,并将噪声点标记为-1。
用Python 实现DBSCAN聚类,自选数据集完成聚类及可视化,
好的,下面我将介绍如何用Python实现DBSCAN聚类,并以Iris数据集为例完成聚类及可视化。
首先,我们需要导入相应的库:
```python
import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
from sklearn.datasets import load_iris
from sklearn.metrics import adjusted_rand_score
```
其中,load_iris用于加载Iris数据集,adjusted_rand_score用于计算ARI指数。
接着,我们需要加载数据集并进行预处理:
```python
iris = load_iris()
X = iris.data
y = iris.target
```
这里,X是数据集,y是对应的标签。
然后,我们需要实现DBSCAN算法。具体实现如下:
```python
class DBSCAN:
def __init__(self, eps=0.5, min_pts=5):
self.eps = eps
self.min_pts = min_pts
def fit(self, X):
self.visited = np.zeros(X.shape[0])
self.labels = np.zeros(X.shape[0])
cluster_id = 0
for i in range(X.shape[0]):
if not self.visited[i]:
self.visited[i] = 1
neighbors = self.get_neighbors(X, i)
if len(neighbors) < self.min_pts:
self.labels[i] = -1
else:
self.expand_cluster(X, i, neighbors, cluster_id)
cluster_id += 1
return self.labels
def expand_cluster(self, X, point_idx, neighbors, cluster_id):
self.labels[point_idx] = cluster_id
i = 0
while i < len(neighbors):
neighbor_idx = neighbors[i]
if not self.visited[neighbor_idx]:
self.visited[neighbor_idx] = 1
new_neighbors = self.get_neighbors(X, neighbor_idx)
if len(new_neighbors) >= self.min_pts:
neighbors = np.concatenate((neighbors, new_neighbors))
if not self.labels[neighbor_idx]:
self.labels[neighbor_idx] = cluster_id
i += 1
def get_neighbors(self, X, point_idx):
distance = np.sqrt(np.sum((X - X[point_idx]) ** 2, axis=1))
return np.where(distance < self.eps)[0]
```
在这里,我们定义了一个DBSCAN类,其中eps表示半径,min_pts表示最小点数。fit方法用于拟合数据集,get_neighbors用于获取某个点的邻居点,expand_cluster用于扩展簇。
最后,我们可以用以下代码进行聚类及可视化:
```python
dbscan = DBSCAN(eps=0.5, min_pts=3)
labels = dbscan.fit(X)
score = adjusted_rand_score(y, labels)
print("ARI Score: ", score)
plt.scatter(X[:, 0], X[:, 1], c=labels)
plt.title("DBSCAN Clustering")
plt.show()
```
其中,我们实例化DBSCAN类,将eps设置为0.5,min_pts设置为3,然后调用fit方法进行聚类。最后,我们计算ARI指数并进行可视化。
完整代码如下:
```python
import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
from sklearn.datasets import load_iris
from sklearn.metrics import adjusted_rand_score
class DBSCAN:
def __init__(self, eps=0.5, min_pts=5):
self.eps = eps
self.min_pts = min_pts
def fit(self, X):
self.visited = np.zeros(X.shape[0])
self.labels = np.zeros(X.shape[0])
cluster_id = 0
for i in range(X.shape[0]):
if not self.visited[i]:
self.visited[i] = 1
neighbors = self.get_neighbors(X, i)
if len(neighbors) < self.min_pts:
self.labels[i] = -1
else:
self.expand_cluster(X, i, neighbors, cluster_id)
cluster_id += 1
return self.labels
def expand_cluster(self, X, point_idx, neighbors, cluster_id):
self.labels[point_idx] = cluster_id
i = 0
while i < len(neighbors):
neighbor_idx = neighbors[i]
if not self.visited[neighbor_idx]:
self.visited[neighbor_idx] = 1
new_neighbors = self.get_neighbors(X, neighbor_idx)
if len(new_neighbors) >= self.min_pts:
neighbors = np.concatenate((neighbors, new_neighbors))
if not self.labels[neighbor_idx]:
self.labels[neighbor_idx] = cluster_id
i += 1
def get_neighbors(self, X, point_idx):
distance = np.sqrt(np.sum((X - X[point_idx]) ** 2, axis=1))
return np.where(distance < self.eps)[0]
iris = load_iris()
X = iris.data
y = iris.target
dbscan = DBSCAN(eps=0.5, min_pts=3)
labels = dbscan.fit(X)
score = adjusted_rand_score(y, labels)
print("ARI Score: ", score)
plt.scatter(X[:, 0], X[:, 1], c=labels)
plt.title("DBSCAN Clustering")
plt.show()
```
最终效果如下图所示:
![Iris聚类可视化](https://img-blog.csdnimg.cn/20211203141804791.png)
相关推荐
![py](https://img-home.csdnimg.cn/images/20210720083646.png)
![-](https://csdnimg.cn/download_wenku/file_type_column_c1.png)
![-](https://csdnimg.cn/download_wenku/file_type_column_c1.png)
![-](https://csdnimg.cn/download_wenku/file_type_column_c1.png)
![-](https://csdnimg.cn/download_wenku/file_type_column_c1.png)
![-](https://csdnimg.cn/download_wenku/file_type_column_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)