Note | Python

1. list method

• index(): Return only the first query to the index value.
  To return plurality, and deriving a list of suggested max()methods, one by one can compare.

2. the

• Check the directory exists, it does not exist, create

  if not os.path.exists(dir_save_stack):
      os.makedirs(dir_save_stack) # 如果是单层目录，可以用mkdir

3. imageio

• Png a grayscale image stored array is
  assumed that the Y channel after treatment, to obtain a between [0,1] as the type np.float32of array output. We want to save the output_pathpath, the steps of: eliminate redundant dimensions B and C => departing from the gradient operation, is transferred to the CPU, it is converted to an array numpy => by 255 => converted to a uint8format => imageio.imwriteSave.

  imageio.imwrite(output_path, ((torch.squeeze(output).detach().cpu().numpy()) * 255).astype(np.uint8))

Warning: I have tried to save as png, the resulting image is a lossy compression. If you need further treatment (such as count psnr), recommended saved as bmp.

4. Python Image Libarary (PIL)

• JPEG compression and save

  from PIL import Image
  img = Image.open("lena.png")
  img.save(img_save_path, "JPEG", quality=quality) # quality = 1 is the worst, quality = 95 is the best

5. random

• Press the seeds upset sequence

  random.seed(17)
  random.shuffle(order)

6. time

• time.time(): Returns units, from January 1970 midnight on the 1st (epoch) elapsed time in seconds.