Is there documentation for file object?

Question

This is probably really dumb question, but I honestly can't find documentation for file object's API in Python 3.

Python docs for things using or returning file objects like open or sys.stdin have links to glossary with high-level introduction. It doesn't list functions exposed by such objects and I don't know, what can I do with them. I've tried googling for file object docs, but search engines don't seem to understand, what am I looking for.

I'm new to Python, but not to programming in general. Until now my scheme of using objects was to find complete API reference, see what it can do and then pick methods to use in my code. Is this wrong mindset in Python world? What are the alternatives?

Answer 1

open returns a file object that differs depending on the mode. From the open docs:

The type of file object returned by the open() function depends on the mode. When open() is used to open a file in a text mode ('w', 'r', 'wt', 'rt', etc.), it returns a subclass of io.TextIOBase (specifically io.TextIOWrapper). When used to open a file in a binary mode with buffering, the returned class is a subclass of io.BufferedIOBase. The exact class varies: in read binary mode, it returns an io.BufferedReader; in write binary and append binary modes, it returns an io.BufferedWriter, and in read/write mode, it returns an io.BufferedRandom. When buffering is disabled, the raw stream, a subclass of io.RawIOBase, io.FileIO, is returned.

Since it varies, open a file object with the mode you want help for and ask it for help:

>>> f = open('xx','w')
>>> help(f)

Help on TextIOWrapper object:

class TextIOWrapper(_TextIOBase)
 |  Character and line based layer over a BufferedIOBase object, buffer.
 |
 : etc...