python中的numpy和pandas---机器学习实战第一篇KNN

http://www.cnblogs.com/prpl/p/5537417.html
熟悉其基本操作

from numpy import *
import operator
def data():
    datas = array([[1.0,1.1],[1.0,1.0],[0,0],[0,0.1]])
    labels = ['A','A','B','B']
    return datas,labels
def classifiaction(a,datas1,labels,k):
    datasize = datas1.shape[0]
    datas2 = tile(a,(datasize,1)) - datas1
    datas3 = datas2**2
    datas4 = datas3.sum(axis=1)
    datas5 = datas4**0.5
    sortdatas6 = datas5.argsort()
    classifiy1 ={}
    for i in range(k):
        m = labels[sortdatas6[i]]
        classifiy1[m]=classifiy1.get(m,0)+1
    sortclassifiy2 = sorted(classifiy1.items(),key=operator.itemgetter(1),reverse=True)
    return sortclassifiy2[0][0]

操作行输入

import knn
datas,labels = knn.data()
datas
labels
knn.classifiaction([0,0],datas,labels,3)