高级numpy布尔索引

import numpy as np

arr = np.array([1, 2, 3, 4, 5])
bool_idx = arr > 2
print(arr[bool_idx])  # 输出: [3 4 5]

import numpy as np

arr = np.array([[1, 2], [3, 4], [5, 6]])
bool_idx = (arr > 2) & (arr < 5)
print(arr[bool_idx])  # 输出: [3 4]

import numpy as np

arr = np.array([1, 2, 3, 4, 5])
bool_idx = arr > 2  # 正确
print(arr[bool_idx])  # 输出: [3 4 5]

# 错误示例
bool_idx_wrong = arr > 2 & arr < 5  # 错误，优先级问题
print(arr[bool_idx_wrong])  # 输出可能不符合预期

# 正确写法
bool_idx_correct = (arr > 2) & (arr < 5)
print(arr[bool_idx_correct])  # 输出: [3 4]

import numpy as np

arr = np.array([[1, 2], [3, 4], [5, 6]])
bool_idx = arr > 2
print(arr[bool_idx])  # 输出: [3 4 5 6]

# 错误示例
bool_idx_wrong = arr > 2 & arr < 5  # 错误，形状不匹配
print(arr[bool_idx_wrong])  # 输出可能不符合预期

# 正确写法
bool_idx_correct = (arr > 2) & (arr < 5)
print(arr[bool_idx_correct])  # 输出: [3 4]