numpy广播

numpy广播入门

不同形状和维度的数组在某些情况下, numpy可以执行加减乘除的运算,这种机制就叫做广播机制

import numpy as np
a = np.arange(3)
b = 1
a + b

a = np.arange(6).reshape(2, 3)
b = np.array([0, 1, 2])
a + b

a = np.arange(6).reshape(2, 3)
b = np.array([0, 1]).reshape(2, 1)
a + b

a = np.arange(6).reshape(2, 3)
b = 2
a + b

a = np.array([0, 3]).reshape(2, 1)
b = np.array([0, 1, 2])
a + b

a = np.arange(6).reshape(2, 3)
b = np.array([0, 1, 2, 3])
a + b
# 维度mismatch