ML之迴歸預測之Lasso：利用Lasso演算法解決迴歸(實數值評分預測)問題—優化模型【增加新(組合)屬性】

輸出結果

設計思路

核心程式碼

names[-1] = "a^2"
names.append("a*b")


nrows = len(xList)
ncols = len(xList[0])

xMeans = []
xSD = []
for i in range(ncols):
    col = [xList[j][i] for j in range(nrows)]
    mean = sum(col)/nrows
    xMeans.append(mean)
    colDiff = [(xList[j][i] - mean) for j in range(nrows)]
    sumSq = sum([colDiff[i] * colDiff[i] for i in range(nrows)])
    stdDev = sqrt(sumSq/nrows)
    xSD.append(stdDev)


X = numpy.array(xList)             #Unnormalized X's
X = numpy.array(xNormalized)       #Normlized Xss
Y = numpy.array(labels)            #Unnormalized labels