python.md

1. Ellipsis (...)

Use cases

• instead of pass

  def some_func()
      ...

2. multi-array slicing

     import numpy as np
     arr = np.array([[[1, 2], [3, 4]], [[5, 6], [7, 8]]])
     print(arr[..., 1])  # Equivalent to arr[:, :, 1]

3. type hinting

     from typing import Any
     def process_data(data: Any, config: ...):
         pass

4. sentinel value

     def my_function(arg=...):
         if arg is ...:
             print("Argument not provided")
         else:
             print("Argument provided:", arg)

5. Required parameters: Some libraries, like typer, use ... to denote required parameters, which must be provided by the user.