Python Topics : Reading a Directory
Getting a List of All Files and Folders in a Directory
to read the contests of a given directory use the Path object's .iterdir() method
when called on a Path object function returns a generator that yields Path objects representing child items
wrap the generator in a list() c'tor, then can see the list of files and folders 
>>> import pathlib
>>> desktop = pathlib.Path("Desktop")

>>> # .iterdir() produces a generator
>>> desktop.iterdir()


>>> # Which you can wrap in a list() constructor to materialize
>>> list(desktop.iterdir())
[WindowsPath('Desktop/Notes'),
 WindowsPath('Desktop/realpython'),
 WindowsPath('Desktop/scripts'),
 WindowsPath('Desktop/todo.txt')]
can use .is_dir() and is_file() methods against the iterator items
Recursively Listing With .rglob()
with pathlib can recurse a directory tree
can use .rglob() to return absolutely everything 
>>> import pathlib
>>> desktop = pathlib.Path("Desktop")

>>> # .rglob() produces a generator too
>>> desktop.rglob("*")


>>> # Which you can wrap in a list() constructor to materialize
>>> list(desktop.rglob("*"))
[WindowsPath('Desktop/Notes'),
 WindowsPath('Desktop/realpython'),
 WindowsPath('Desktop/scripts'),
 WindowsPath('Desktop/todo.txt'),
 WindowsPath('Desktop/Notes/hash-tables.md'),
 WindowsPath('Desktop/realpython/iterate-dict.md'),
 WindowsPath('Desktop/realpython/tictactoe.md'),
 WindowsPath('Desktop/scripts/rename_files.py'),
 WindowsPath('Desktop/scripts/request.py')]
the .rglob() method with "*" as an argument produces a generator which yields all the files and folders from the Path object recursively
Using a Glob Pattern for Conditional Listing

sometimes just want one type of file or directory or all the items with a certain pattern of characters in their name
a method related to .rglob() is the .glob() method
both use of glob patterns
a glob pattern represents a collection of paths
glob patterns make use of wildcard characters to match on certain criteria

Glob PatternMatches
*every item
*.txtevery item ending in .txt
??????every item whose name is six characters long
A* avery item that starts with the character A
case-insensitive under Windows
under 'nix and macOS patterns are case sensitive
[abc][abc][abc] every item whose name is three characters long but only composed of the characters a, b, and c,
Conditional Listing Using .glob()
the .glob() method of a Path object behaves in much the same way as .rglob()
if passed the "*" argument, then a list of items in the directory will be returned but without recursion 
>>> import pathlib
>>> desktop = pathlib.Path("Desktop")

>>> # .glob() produces a generator too
>>> desktop.glob("*")


>>> # Which you can wrap in a list() constructor to materialize
>>> list(desktop.glob("*"))
[WindowsPath('Desktop/Notes'),
 WindowsPath('Desktop/realpython'),
 WindowsPath('Desktop/scripts'),
 WindowsPath('Desktop/todo.txt')]
filtering with different patterns 
>>> desktop = pathlib.Path("Desktop")
>>> list(desktop.glob("*.txt"))
[WindowsPath('Desktop/todo.txt')]

>>> list(desktop.glob("real*"))
[WindowsPath('Desktop/realpython')]

>>> list(desktop.glob("realpython/*"))
[WindowsPath('Desktop/realpython/iterate-dict.md'),
 WindowsPath('Desktop/realpython/tictactoe.md')]
Conditional Listing Using .rglob()
.rglob() always searches recursively
filtering with different patterns 
>>> list(desktop.rglob("*.md"))
[WindowsPath('Desktop/Notes/hash-tables.md'),
 WindowsPath('Desktop/realpython/iterate-dict.md'),
 WindowsPath('Desktop/realpython/tictactoe.md')]

>>> list(desktop.glob("**/*.md"))
[WindowsPath('Desktop/Notes/hash-tables.md'),
 WindowsPath('Desktop/realpython/iterate-dict.md'),
 WindowsPath('Desktop/realpython/tictactoe.md')]
Advanced Matching With the Glob Methods
one potential drawback with the glob methods is can only select files based on glob patterns
to do more advanced matching or filter on the attributes of the item, can follow at least three strategies
  1. a for loop with a conditional check
  2. a comprehension with a conditional expression
  3. the built-in filter() function
examples 
>>> import pathlib
>>> desktop = pathlib.Path("Desktop")

>>> # Using a for loop
>>> for item in desktop.rglob("*"):
...     if item.is_file():
...         print(item)
...
Desktop\todo.txt
Desktop\Notes\hash-tables.md
Desktop\realpython\iterate-dict.md
Desktop\realpython\tictactoe.md
Desktop\scripts\rename_files.py
Desktop\scripts\request.py

>>> # Using a comprehension
>>> [item for item in desktop.rglob("*") if item.is_file()]
[WindowsPath('Desktop/todo.txt'),
 WindowsPath('Desktop/Notes/hash-tables.md'),
 WindowsPath('Desktop/realpython/iterate-dict.md'),
 WindowsPath('Desktop/realpython/tictactoe.md'),
 WindowsPath('Desktop/scripts/rename_files.py'),
 WindowsPath('Desktop/scripts/request.py')]

>>> # Using the filter() function
>>> list(filter(lambda item: item.is_file(), desktop.rglob("*")))
[WindowsPath('Desktop/todo.txt'),
 WindowsPath('Desktop/Notes/hash-tables.md'),
 WindowsPath('Desktop/realpython/iterate-dict.md'),
 WindowsPath('Desktop/realpython/tictactoe.md'),
 WindowsPath('Desktop/scripts/rename_files.py'),
 WindowsPath('Desktop/scripts/request.py')]
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