def format_3d(df): X = np.array(df) return np.reshape(X, (X.shape[0], X.shape[1], 1))代码讲解
时间: 2023-06-20 18:04:27 浏览: 56
这是一个Python函数,其功能是将一个Pandas DataFrame格式的数据转换为一个3D Numpy数组。具体的实现步骤如下:
1. 将输入的DataFrame转换为一个Numpy数组,这里使用了NumPy库中的array函数。
2. 使用NumPy库中的reshape函数,将原数组重新排列成一个三维数组。
该函数的参数为一个DataFrame对象df,返回值为一个3D Numpy数组。具体实现如下:
```python
import numpy as np
import pandas as pd
def format_3d(df):
X = np.array(df) # 将df转换为Numpy数组
return np.reshape(X, (X.shape[0], X.shape[1], 1)) # 将Numpy数组重新排列成3D数组
```
例如,将一个2x3的DataFrame对象df转换为3D Numpy数组,可以通过以下代码实现:
```python
df = pd.DataFrame([[1, 2, 3], [4, 5, 6]])
X_3d = format_3d(df)
print(X_3d.shape) # 输出(2, 3, 1)
```
输出结果为(2, 3, 1),表示转换后的3D数组有2个样本,每个样本有3个特征,每个特征只有1个值。
相关问题
程序执行提示AttributeError: 'point_cloud_generator' object has no attribute 'widthself',优化程序class point_cloud_generator(): def __init__(self, rgb_file, depth_file, save_ply, camera_intrinsics=[784.0, 779.0, 649.0, 405.0]): self.rgb_file = rgb_file self.depth_file = depth_file self.save_ply = save_ply self.rgb = cv2.imread(rgb_file) self.depth = cv2.imread(self.depth_file, -1) print("your depth image shape is:", self.depth.shape) self.width = self.rgb.shape[1] self.height = self.rgb.shape[0] self.camera_intrinsics = camera_intrinsics self.depth_scale = 1000 def compute(self): t1 = time.time() depth = np.asarray(self.depth, dtype=np.uint16).T # depth[depth==65535]=0 self.Z = depth / self.depth_scale fx, fy, cx, cy = self.camera_intrinsics X = np.zeros((self.width, self.height)) Y = np.zeros((self.width, self.height)) for i in range(self.width): X[i, :] = np.full(X.shape[1], i) self.X = ((X - cx / 2) * self.Z) / fx for i in range(self.height): Y[:, i] = np.full(Y.shape[0], i) self.Y = ((Y - cy / 2) * self.Z) / fy data_ply = np.zeros((6, self.width * self.height)) data_ply[0] = self.X.T.reshape(-1)[:self.widthself.height] data_ply[1] = -self.Y.T.reshape(-1)[:self.widthself.height] data_ply[2] = -self.Z.T.reshape(-1)[:self.widthself.height] img = np.array(self.rgb, dtype=np.uint8) data_ply[3] = img[:, :, 0:1].reshape(-1)[:self.widthself.height] data_ply[4] = img[:, :, 1:2].reshape(-1)[:self.widthself.height] data_ply[5] = img[:, :, 2:3].reshape(-1)[:self.widthself.height] self.data_ply = data_ply t2 = time.time() print('calcualte 3d point cloud Done.', t2 - t1)
在代码中有两处出现了 `self.widthself.height`,这应该是想要写成 `self.width * self.height`。你需要修改这两处,如下所示:
```
data_ply[0] = self.X.T.reshape(-1)[:self.width * self.height]
data_ply[1] = -self.Y.T.reshape(-1)[:self.width * self.height]
data_ply[2] = -self.Z.T.reshape(-1)[:self.width * self.height]
img = np.array(self.rgb, dtype=np.uint8)
data_ply[3] = img[:, :, 0:1].reshape(-1)[:self.width * self.height]
data_ply[4] = img[:, :, 1:2].reshape(-1)[:self.width * self.height]
data_ply[5] = img[:, :, 2:3].reshape(-1)[:self.width * self.height]
```
这样就可以避免出现 `AttributeError: 'point_cloud_generator' object has no attribute 'widthself'` 的错误了。
import numpy as np from scipy.optimize import linprog def integer_cutting_plane(c, A, b, bounds): relaxed_A = A relaxed_b = b while True: res = linprog(c=c, A_ub=relaxed_A, b_ub=relaxed_b, bounds=bounds) x = res.x if all(int(val) == val for val in x): return x.astype(int) new_constraint = (relaxed_A @ x <= relaxed_b) relaxed_A = np.vstack((relaxed_A, new_constraint)) def get_bounds(): return [(0, None), (0, None)] def get_c(): return np.array([40, 90]) def get_A(): return np.array([[-9, -7], [-7, -20]]) def get_b(): return np.array([-56, -70]) if __name__ == '__main__': bounds = get_bounds() integer_cutting_plane(get_c(), get_A(), get_b(), bounds)以上代码运行报错ValueError: Invalid input for linprog: b_ub must be a 1-D array; b_ub must not have more than one non-singleton dimension and the number of rows in A_ub must equal the number of values in b_ub 请解决
在你的代码中,报错是因为在调用linprog函数时,传递给参数b_ub的参数relaxed_b是一个二维数组。linprog函数要求b_ub是一个一维数组。
要解决这个问题,你可以使用numpy库的flatten()方法将relaxed_b转换为一维数组。flatten()方法会将多维数组展平为一维数组。
以下是修改后的代码:
```python
import numpy as np
from scipy.optimize import linprog
def integer_cutting_plane(c, A, b, bounds):
relaxed_A = A
relaxed_b = b
while True:
res = linprog(c=c, A_ub=relaxed_A, b_ub=relaxed_b.flatten(), bounds=bounds)
x = res.x
if all(int(val) == val for val in x):
return x.astype(int)
new_constraint = (relaxed_A @ x <= relaxed_b)
relaxed_A = np.vstack((relaxed_A, new_constraint))
def get_bounds():
return [(0, None), (0, None)]
def get_c():
return np.array([40, 90])
def get_A():
return np.array([[-9, -7], [-7, -20]])
def get_b():
return np.array([-56, -70])
if __name__ == '__main__':
bounds = get_bounds()
integer_cutting_plane(get_c(), get_A(), get_b(), bounds)
```
通过使用flatten()方法将relaxed_b转换为一维数组,你可以解决报错问题。请注意,这里使用的是numpy库的flatten()方法,而不是reshape()方法。