如何将列表合并到嵌套列表？

Question

我有一个列表（虹膜数据样本），我想缩放变量（除了最后一列）。我做了一个循环来做到这一点，但我不知道如何在这个过程之后合并它们。X = [[5.1, 3.5, 1.4, 0.2, 0.0],     [4.9, 3.0, 1.4, 0.2, 0.0],     [4.7, 3.2, 1.3, 0.2, 0.0],     [4.6, 3.1, 1.5, 0.2, 0.0],     [5.0, 3.6, 1.4, 0.2, 0.0],     [5.4, 3.9, 1.7, 0.4, 0.0]]我试图做一个循环来缩放，但我不知道如何合并。我试过了：from statistics import mean, stdevfor i in range(len(X)):    valores = []    for j in range(len(X[i])-1):        z = []        coluna = [item[j] for item in X]        media = mean(coluna)        desv = stdev(coluna)        z = [round(((x - media) / desv), 4) for x in coluna]        valores = valores + zvalores = valores + [valor[-1] for valor in X]我的实际结果是：valores = [0.5207,-0.1736,-0.8678,-1.2149,0.1736,1.562,0.3401,-1.1175,-0.5345,-0.826,0.6316,1.5062,-0.3627,-0.3627,-1.0882,0.3627,-0.3627,1.8137,-0.4082,-0.4082,-0.4082,-0.4082,-0.4082,2.0412,0.0,0.0,0.0,0.0,0.0,0.0]但我想得到：valores = [[0.5207, 0.3401, -0.3627, -0.4082, 0.0],           [-0.1736, -1.1175, -0.3627, -0.4082, 0.0],           [-0.8678, -0.5345, -1.0882, -0.4082, 0.0],           [-1.2149, -0.826, 0.3627, -0.4082, 0.0],           [0.1736, 0.6316, -0.3627, -0.4082, 0.0],           [1.562, 1.5062, 1.8137, 2.0412, 0.0]]

Answer 1

使用熊猫：

数据：

X = [[5.1, 3.5, 1.4, 0.2, 0.0],

     [4.9, 3.0, 1.4, 0.2, 0.0],

     [4.7, 3.2, 1.3, 0.2, 0.0],

     [4.6, 3.1, 1.5, 0.2, 0.0],

     [5.0, 3.6, 1.4, 0.2, 0.0],

     [5.4, 3.9, 1.7, 0.4, 0.0]]

代码：

编写函数def valores以产生所需的转换

创建一个数据框X

应用于valores数据框中的相应列

import pandas as pd

def valores(x):

    return [round(((y - x.mean()) / x.std()), 4) for y in x]

df = pd.DataFrame(X)

df[[0, 1, 2, 3]] = df[[0, 1, 2, 3]].apply(lambda x: valores(x))

输出：

      0       1       2       3    4

 0.5207  0.3401 -0.3627 -0.4082  0.0

-0.1736 -1.1175 -0.3627 -0.4082  0.0

-0.8678 -0.5345 -1.0882 -0.4082  0.0

-1.2149 -0.8260  0.3627 -0.4082  0.0

 0.1736  0.6316 -0.3627 -0.4082  0.0

 1.5620  1.5062  1.8137  2.0412  0.0

Answer 2

不优雅：

out = []

for i in range(1+len(valores)//len(X)):

    aux = []

    for j in range(len(X[0])):

        aux.append(valores[i+len(X)*j])

    out.append(aux)

print(out)

[[0.5207, 0.3401, -0.3627, -0.4082, 0.0], [-0.1736, -1.1175, -0.3627, -0.4082, 0.0], [-0.8678, -0.5345, -1.0882, -0.4082, 0.0], [-1.2149, -0.826, 0.3627, -0.4082, 0.0], [0.1736, 0.6316, -0.3627, -0.4082, 0.0], [1.562, 1.5062, 1.8137, 2.0412, 0.0]]