Python combine numpy arrays with indices-CodePudding

import numpy as np

arr1 = np.array([0, 1, 2, 3]).reshape(1, 4)
arr2 = np.array([0, 1, 2, 3, 4, 5]).reshape(1, 6)
arr3 = np.array([0, 1, 4, 3, 5]).reshape(1, 5)
list_off_arrs = [arr1, arr2, arr3]
# expected output:
# ndarray -> [[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 14, 13, 15]]

I want to take a list of numpy arrays that are all one dimensional and contain index values, and combine them as shown above. Is there a quick way to do something like this?

CodePudding user response：

Here's one approach:

import numpy as np

arr1 = np.array([0, 1, 2, 3]).reshape(1, 4)
arr2 = np.array([0, 1, 2, 3, 4, 5]).reshape(1, 6)
arr3 = np.array([0, 1, 4, 3, 5]).reshape(1, 5)
list_of_arrs = [arr1, arr2, arr3]

n = len(list_of_arrs)
for i in range(n):
    for j in range(i):
        list_of_arrs[i]  = list_of_arrs[j].shape[1]
print(np.hstack(list_of_arrs))

Result:

[[ 0  1  2  3  4  5  6  7  8  9 10 11 14 13 15]]

CodePudding user response：

Use numpy.concatenate

>>> arr2  = arr1[0, -1]   1
>>> arr3  = arr2[0, -1]   1
>>> np.concatenate([arr1, arr2, arr3], axis=1)
array([[ 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 14, 13, 15]])