一文详解NumPy分割与搜索数组

np.array_split(array, indices_or_sections, axis=None)

import numpy as np

arr = np.array([1, 2, 3, 4, 5, 6])

# 将数组分割成 3 个子数组
new_arrays = np.array_split(arr, 3)
print(new_arrays)  # 输出：
                        # [array([1, 2]), array([3, 4]), array([5, 6])]

# 指定分割位置
new_arrays = np.array_split(arr, [2, 5])
print(new_arrays)  # 输出：
                        # [array([1, 2]), array([3, 4]), array([5, 6])]

# 沿列分割
arr = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
new_arrays = np.array_split(arr, 3, axis=1)
print(new_arrays)  # 输出：
                        # [array([[1, 4, 7]]), array([[2, 5, 8]]), array([[3, 6, 9]])]

import numpy as np

arr = np.array([1, 2, 3, 4, 5, 6])
mask = arr % 2 == 0
new_arrays = np.array_split(arr, mask)
print(new_arrays)  # 输出：
                        # [array([2, 4, 6]), array([1, 3, 5])]

import numpy as np

arr = np.array([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12])

np.where(condition)

import numpy as np

arr = np.array([1, 2, 3, 4, 5, 6, 7, 8, 9])

# 查找值为 4 的索引
indices = np.where(arr == 4)
print(indices)  # 输出： (array([3, 5, 6]),)

# 查找大于 5 的元素的索引
indices = np.where(arr > 5)
print(indices)  # 输出： (array([6, 7, 8]),)

np.searchsorted(array, value, side='left')

import numpy as np

arr = np.array([1, 3, 5, 7, 9])

# 查找值 7 应插入的索引
index = np.searchsorted(arr, 7)
print(index)  # 输出： 3

# 从右侧查找值 2 应插入的索引
index = np.searchsorted(arr, 2, side='right')
print(index)  # 输出： 1

import numpy as np

arr = np.array([1, 2, 3, 4, 3, 3, 6, 7, 8])