numpy_合并

import numpy as np

a = np.array([1, 2, 3])
b = np.array([9, 8, 7])

# 对a b进行垂直合并---vsstack(vertical stack)
c = np.vstack((a, b))
print(c.shape)
print(c)

# 对a b进行水平合并---hstack(horizontal stack)
d = np.hstack((a, b))
print(d.shape)
print(d)

# 冒号在前，列维度加1 ；冒号在后，行维度加1
print(a.shape)  # (3,)
print(a[:, np.newaxis].shape)  # (3,1)
print(a[np.newaxis, :].shape)  # (1,3)
print(a[np.newaxis, :])  # [[1 2 3]]

# 使用concatenate指定纵向或横向合并(axis=0表示纵向，axis=1横向)
a = np.array([1, 2, 3])[:, np.newaxis]
b = np.array([9, 8, 7])[:, np.newaxis]
c = np.concatenate((a, b, b, a), axis=1)
print(c)
d = np.concatenate((a,b,b,a),axis=0)
print(d)