Import functions

• Some useful functions require you to import them before you start using them. For example, we did from sys import argv This is a function from the standard Python library, but we cannot use this function if we don’t import it (要使用library function 前要先import )

• python 中有些基本function 是已經內建 ex print() , 有些是要把module import 後才能調用 ex import random module, 調用 random.radiant() / import math

• Some other common modules include:

  • requests, bs4 (for web scraping)
  • numpy, pandas, matplotlib, seaborn (data visualization)random,
  • sklearn, tensorflow (machine learning, deep learning)

Why is Python designed in this way?

• There is less to compile and run by default. Your program will load faster, because it only knows about the parts of Python that it actually needs.
  • 只調用有import 的module
• It keeps the global namespace clean and allows functionality to be grouped logically into modules.
  • global namespace ex: print() 已經被分好
• Different modules can have identically-named functions without clashes (file and socket class would probably both have open and close functions, for example). It makes sure we don’t mess up the names.
  • 不同的module 可能有 def 定義到同樣的function ，用import 的方式可避免mess up
  • 其它的語言是如何應用 ??