expand_dims() i newaxis() NumPy

Przykłady dodawania nowych wymiarów w bibliotece NumPy:

1. Dodawanie nowego wymiaru – tablica 1D:

import numpy as np

# Tworzenie tablicy 1D
a = np.array([1, 2, 3])
print(a.shape)  # (3,)


b = np.expand_dims(a, axis=0)
print(b.shape)  # (1, 3)

import numpy as np

# Tworzenie tablicy 1D
a = np.array([1, 2, 3])
print(a.shape)  # (3,)

b = a[:, np.newaxis]
print(b.shape)  # (3, 1)

2. Dodawanie nowego wymiaru – tablica 2D:

import numpy as np

# Tworzenie tablicy 2D
a = np.array([[1, 2],
              [3, 4]])
print(a.shape)  # (2, 2)


b = np.expand_dims(a, axis=2)
print(b.shape)  # (2, 2, 1)

import numpy as np

# Tworzenie tablicy 2D
a = np.array([[1, 2],
              [3, 4]])
print(a.shape)  # (2, 2)


b = a[:, :, np.newaxis]
print(b.shape)  # (2, 2, 1)

3. Dodawanie nowego wymiaru – macierz 3D:

import numpy as np

# Tworzenie tablicy 3D
a = np.array([[[1, 2],
               [3, 4]],
              [[5, 6],
               [7, 8]]])
print(a.shape)  # (2, 2, 2)


b = np.expand_dims(a, axis=3)
print(b.shape)  # (2, 2, 2, 1)

import numpy as np

# Tworzenie tablicy 3D
a = np.array([[[1, 2],
               [3, 4]],
              [[5, 6],
               [7, 8]]])
print(a.shape)  # (2, 2, 2)

b = a[:, :, :, np.newaxis]
print(b.shape)  # (2, 2, 2, 1)