import numpy as nparr = np.array([1,2,3,4,5,6,7,8,9])# 筛选大于5的元素mask = arr > 5result = arr[mask]print("大于5的元素：", result)# 多维数组条件筛选arr2 = np.array([[1,12,3],[4,15,6]])print("大于10的元素：", arr2[arr2>10])

a = np.array([[1,2],[3,4]])b = np.array([[5,6],[7,8]])# 横向拼接h_stack = np.hstack((a,b))# 纵向拼接v_stack = np.vstack((a,b))# 数组拆分split_arr = np.hsplit(h_stack, 2)print("横向拼接：\n", h_stack)print("纵向拼接：\n", v_stack)

arr = np.array([1,2,3,4])# 转换为浮点型arr_float = arr.astype(np.float64)print(f"arr_float = {arr_float}, 类型为 {arr_float.dtype}")# 缺失值处理arr_nan = np.array([1,2,np.nan,4,5])print(f"arr_nan = {arr_nan}")# 去除缺失值arr_no_nan = arr_nan[~np.isnan(arr_nan)]print(f"arr_no_nan = {arr_no_nan}")# 缺失值替换为均值arr_replace = np.nan_to_num(arr_nan, nan=np.nanmean(arr_nan))print(f"arr_replace = {arr_replace}")

arr = np.array([3,1,4,1,5,9,2,6])# 数组排序arr_sort = np.sort(arr)# 数组去重arr_unique = np.unique(arr)print("排序后：", arr_sort)print("去重后：", arr_unique)