ps:np.min/np.minimum同理
ps:这里只介绍最常用的功能,详细功能请查看官方文档
1. np.max 计算一个数组中的最值
(1)基础用法
a = np.array([
[1, 2, 3],
[4, 5, 6],
[7, 8, 9]
])
print(np.max(a))
print(np.max(a, axis=0))
print(np.max(a, axis=1))
[Out]:
9
[7 8 9]
[3 6 9]
(2)keepdims:维持形状
print(np.max(a, keepdims=True))
print(np.max(a, axis=0, keepdims=True))
print(np.max(a, axis=1, keepdims=True))
[Out]:
[[9]]
[[7 8 9]]
[[3]
[6]
[9]]
(3)initial:指定最小值
print(np.max(a, initial=8))
print(np.max(a, axis=0, initial=8))
print(np.max(a, axis=1, initial=8))
[Out]:
9
[8 8 9]
[8 8 9]
(4)where:指定参与比较的元素,不参与的置initial值
print(np.max(a, initial=8, where=[1, 1, 0]))
print(np.max(a, axis=0, initial=8, where=[True, True, False]))
print(np.max(a, axis=1, initial=8, where=[True, True, False]))
[Out]:
8
[8 8 8]
[8 8 8]
2. np.maximum 比较两个数组的最值
a = np.array([
[1, 2, 3],
[4, 5, 6]
])
b = np.array([
[7, 8, 9],
[0, 1, 2]
])
print(np.maximum(a, b))
print(np.maximum(a, 3.5))
[Out]:
[[7 8 9]
[4 5 6]]
[[3.5 3.5 3.5]
[4. 5. 6. ]]