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k-mearns算法以k为参数,把n个对象分成k个簇,使簇内具有较高的相似度,而簇间的相似度较低
1、随机选择k个点作为初始的聚类中心
2、对于剩下的点,根据其与聚类中心的距离,将其归入最近的簇
3、对每个簇,计算所有点的均值作为新的取类中心
4、重复2、3直到取类中心不再发生改变
拓展
计算两条数据相似性时,sklearn.K-Means默认用欧式距离,
虽然还有余弦相似度,马氏距离等多种方法,但没有设定计算距离方法的参数
数据介绍:
现有1999年全国31个省份城镇居民家庭平均每月全年消费性支出 的八个主要变量数据,这八个变量分别是
食品、衣着、家庭设备用品、服务、医疗保健、交通、通讯、娱乐教育文化服务、居住以及杂项商品和服务。
利用已有数据,对31个省份进行聚类
通过聚类,了解1999年各个省份的消费水平在国内的情况
sklearn.cluster.Kmeans
‘E:\python\Spyder_analysis\课程数据’1
1、使用算法:K-means聚类算法
2、实现过程:
1、建立工程,导入sklearn相关包
import numpy as np
from sklearn.cluster import KMeans
2、加载数据,创建K-means算法实例,并进行训练,获得标签
3、输出标签,查看结果
将城市按照消费水平n_clusters类,消费水平相近的城市聚集在一类中
expense:聚类中心点的数值加和,也就是平均消费水平
调用K-Means方法所需参数:
km=KMeans(n_clusters=8,init=‘k-means++’,n_init=10,max_iter=300,tol=1e-4,
precompute_distances=‘auto’,verbose=0,random_state=None,
copy_x=True,n_jobs=None,algorithm=‘auto’)
n_clusters:用于指定取类中心的个数
init:初始聚类中心的初始化方法
max_iter:最大迭代次数
一般调用 时只用给出n_clusters即可,init默认是k-means++,max_iter默认是300
其他参数:
data:加载的数据
label:聚类后各数据所属的标签
fit_predict():计算簇中心以及为簇分配序号
import numpy as np from sklearn.cluster import KMeans #定义数据导入方法 def loadData(filePath): fr=open(filePath,'r+') #读写打开一个文本文件 lines=fr.readlines() #一次读取整 个文件(类似于.read()) retData=[] #城市各项信息 retCityName=[] #城市名称 for line in lines: items=line.strip().split(",") retCityName.append(items[0]) retData.append([items[i] for i in range(1,len(items))]) #print(retCityName) return retData,retCityName #加载数据,创建K-means算法实例,并进行训练,获得标签 if __name__=='__main__': filepath='E:/python/Spyder_analysis/课程数据/聚类/31省市居民家庭消费水平-city.txt' data,cityName=loadData(filepath) #利用loadData方法读取数据 km=KMeans(n_clusters=3) #创建实例 label=km.fit_predict(data) #调用Kmeans() fit_predict()方法进行计算 expenses=np.sum(km.cluster_centers_,axis=1) #print(expenses) CityCluster=[[],[],[]] #将城市 按label分成设定的簇,将每个簇的城市输出 for i in range(len(cityName)): CityCluster[label[i]].append(cityName[i]) for i in range(len(CityCluster)): print("Expenses:%.2f" %expenses[i]) print(CityCluster[i])
数据
北京,2959.19,730.79,749.41,513.34,467.87,1141.82,478.42,457.64
天津,2459.77,495.47,697.33,302.87,284.19,735.97,570.84,305.08
河北,1495.63,515.90,362.37,285.32,272.95,540.58,364.91,188.63
山西,1406.33,477.77,290.15,208.57,201.50,414.72,281.84,212.10
内蒙古,1303.97,524.29,254.83,192.17,249.81,463.09,287.87,192.96
辽宁,1730.84,553.90,246.91,279.81,239.18,445.20,330.24,163.86
吉林,1561.86,492.42,200.49,218.36,220.69,459.62,360.48,147.76
黑龙江,1410.11,510.71,211.88,277.11,224.65,376.82,317.61,152.85
上海,3712.31,550.74,893.37,346.93,527.00,1034.98,720.33,462.03
江苏,2207.58,449.37,572.40,211.92,302.09,585.23,429.77,252.54
浙江,2629.16,557.32,689.73,435.69,514.66,795.87,575.76,323.36
安徽,1844.78,430.29,271.28,126.33,250.56,513.18,314.00,151.39
福建,2709.46,428.11,334.12,160.77,405.14,461.67,535.13,232.29
江西,1563.78,303.65,233.81,107.90,209.70,393.99,509.39,160.12
山东,1675.75,613.32,550.71,219.79,272.59,599.43,371.62,211.84
河南,1427.65,431.79,288.55,208.14,217.00,337.76,421.31,165.32
湖南,1942.23,512.27,401.39,206.06,321.29,697.22,492.60,226.45
湖北,1783.43,511.88,282.84,201.01,237.60,617.74,523.52,182.52
广东,3055.17,353.23,564.56,356.27,811.88,873.06,1082.82,420.81
广西,2033.87,300.82,338.65,157.78,329.06,621.74,587.02,218.27
海南,2057.86,186.44,202.72,171.79,329.65,477.17,312.93,279.19
重庆,2303.29,589.99,516.21,236.55,403.92,730.05,438.41,225.80
四川,1974.28,507.76,344.79,203.21,240.24,575.10,430.36,223.46
贵州,1673.82,437.75,461.61,153.32,254.66,445.59,346.11,191.48
云南,2194.25,537.01,369.07,249.54,290.84,561.91,407.70,330.95
西藏,2646.61,839.70,204.44,209.11,379.30,371.04,269.59,389.33
陕西,1472.95,390.89,447.95,259.51,230.61,490.90,469.10,191.34
甘肃,1525.57,472.98,328.90,219.86,206.65,449.69,249.66,228.19
青海,1654.69,437.77,258.78,303.00,244.93,479.53,288.56,236.51
宁夏,1375.46,480.89,273.84,317.32,251.08,424.75,228.73,195.93
新疆,1608.82,536.05,432.46,235.82,250.28,541.30,344.85,214.40 ↩︎
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