How can i learn modules?

Question

Some modules are very useful while making a programme...
I wants to know about when i should use an appropriate module according to the situation.
And how many modules are there in Python?

Answer 1

Import module in python
Use help(module) to get its inbuilt documentation.

Which is very helpful for developers

And also you can use dir to see all available methods and properties in classes

Answer 2

丹ⓨㄩک廾 thnx