python - 通过 Numpy/Pandas 使用 (n x 1) 数据创建一个 n x m 多项式数组

Question

我使用以下方法创建了一个数组:

𝑥𝑖 = np.random.normal(0,1,50), which gave me
array([ 1.92024714, -0.19882742, -0.26836024,  0.32805879, -0.32085809,
       -0.23569939,  0.22310599,  0.5483915 , -0.13106083, -1.03798811,
        0.4586899 , -1.7378367 , -0.49868295,  1.58943447,  0.92153814,
        0.38894787, -1.26605208,  0.44308314,  1.10222734,  0.40031394,
       -1.2126154 ,  0.26871733, -0.85161259,  0.15853002, -0.18531145,
       -0.18069696,  0.19121711,  0.16586507,  0.43668293,  0.38395065,
       -1.02418998,  0.10464186, -0.02777545, -0.30571787,  1.0690931 ,
       -0.67266002,  2.00256049, -0.05156432, -1.03735733,  0.27650841,
       -0.53300549, -0.4301668 ,  1.01371008, -0.70780846,  0.11577668,
        0.19328765, -0.72971236,  1.61804424, -0.69770352, -1.33161613])

对于这个数组的每个元素，我如何才能得到一个 50x3 的矩阵，就像这样——有什么建议吗？

𝑥1^1     𝑥1^2     𝑥1^3
𝑥2^1     𝑥2^2     𝑥2^3
𝑥3^1     𝑥3^2     𝑥3^3
.
.
𝑥50^1     𝑥50^2     𝑥50^3

即上面 50x1 数组中的数字在 50 x 3 数组中看起来是这样的

1.92024714     3.68734907867818      7.08062152251341
-0.19882742    0.03953234294385     -0.00786011375408 
-0.26836024     0.07201721841285     -0.01932655801740
. 
.
.
.
.
-1.33161613     1.77320151767618     -2.36122374267808

Answer 1

使用 np.column_stack

np.column_stack((a, a**2, a**3))

---

array([[ 1.92024714e+00,  3.68734908e+00,  7.08062152e+00],
       [-1.98827420e-01,  3.95323429e-02, -7.86011375e-03],
              ...      ,        ...     ,       ...
       [-6.97703520e-01,  4.86790202e-01, -3.39635237e-01],
       [-1.33161613e+00,  1.77320152e+00, -2.36122374e+00]])