在 Python 中转置、旋转和组合 2D arrays

Question

I have a 2D array, and it size is 93 X 93.

import numpy as np
import matplotlib.pyplot as plt

size = 93

arr2D = np.eye(size, size, dtype=float)
for i in range(size):
    for j in range(size):
        arr2D[i][j] = np.arctan((i+1)/(j+1))

arr2D = np.cos(arr2D)

plt.imshow(arr2D)
plt.colorbar(fraction=0.0455)
plt.show()

I would like to create 4 same arrays, transpose, and combine them (size: 186 X 186) to make them look like the figure below, how can I do this?

Answer 1

you can use np.flipud and np.fliplr for flipping and np.vstack and np.c_ for stacking

stacked_arr = np.c_[np.fliplr(arr2D),arr2D]
stacked_arr_flipped = np.flipud(np.c_[np.fliplr(arr2D),arr2D])
new_arr = np.vstack((stacked_arr_flipped ,stacked_arr ))

plt.imshow(new_arr)
plt.colorbar(fraction=0.0455)
plt.show()