替换np.array中元素的快速方法

import numpy as np

arr = np.array([1, 2, 3, 4, 5])
arr[2] = 10  # 替换第3个元素
print(arr)  # 输出: [ 1  2 10  4  5]

import numpy as np

arr = np.array([1, 2, 3, 4, 5])
arr[1:4] = [20, 30, 40]  # 替换第2到第4个元素
print(arr)  # 输出: [ 1 20 30 40  5]

import numpy as np

arr = np.array([1, 2, 3, 4, 5])
arr[arr > 2] = 99  # 将大于2的元素替换为99
print(arr)  # 输出: [ 1  2 99 99 99]

import numpy as np

arr = np.random.rand(1000, 1000)
new_values = np.random.rand(1000, 1000)
mask = arr > 0.5
arr[mask] = new_values[mask]  # 使用条件索引和广播机制