Question

I am going over a Python tutorial the one where the following example is demonstrated:

>>> 'str'.strip() + 'ing'   #  <-  This is ok

In this example (as i understand it) str is a string, on which function strip() is called.

I would reasonably expect to find that function doing >>> dir("abc"). Indeed function is listed as 'strip'

Question 1: Why are some functions listed as __name__ and others as name?

Question 2: I would like now to find more information about this function. When running help("abc") (expecting to get a man page on all functions that can be ran on string), strip is not listed. Why? Where can i find out more about particular function?

Question 3: Using PyCharm i would expect the following autocompletion to work and yet, i see nothing. Why is that?

Answer 1

1. Functions surrounded by double underscores are special functions that can be overridden to implement special behaviors. For example, the __getitem__ function, when implemented in a class, allows indexed access to items in that class. (In other words, a[5] is equivalent in most contexts to a.__getitem__(5)). The underscores just signal that they’re special, and require some special handling. (For example, don’t invent your own.)

2. When you pass a string to help, it treats the string as a query. For example, help('class') brings up a bunch of information about classes. If you want the help text for string objects, do help(str) or help('str').

3. I don’t use PyCharm, so I can’t help there.