机器学习K-Means中TypeError: unsupported operand type(s) for -: 'map' and 'map'

TypeError: unsupported operand type(s) for -: ‘map’ and ‘map’
书中源代码如下：

from numpy import *
def loadDataSet(fileName):
    dataMat = []
    fr = open(fileName)
    for line in fr.readlines():
        curLine = line.strip().split('\t')
		fltLine = map(float, curLine)
        dataMat.append(fltLine)
    return dataMat

def distEclud(vecA, vecB):
    return sqrt(sum(power(vecA - vecB, 2)))
    
def randCent(dataSet, k):
    n = shape(dataSet)[1]
    centroids = mat(zeros((k, n)))
    for j in range(n):
        minJ = min(dataSet[:, j])
        rangeJ = float(max(dataSet[:, j]) - minJ)
        centroids[:, j] = minJ + rangeJ * random.rand(k, 1)
    return centroids

按照书中敲入代码kmeans.randCent(dataSet, 2)出现错误如下：

TypeError: unsupported operand type(s) for -: 'map' and 'map'

即rangeJ = float(max(dataSet[:, j]) - minJ)相减的是两个map类型的数据，经过查找，发现fltLine = map(float, curLine)在python2中返回的是一个list类型数据，而在python3中该语句返回的是一个map类型的数据。
因此，我们只需要将该语句改为fltLine = list(map(float, curLine)),错误就解决啦。