File path

A file path, or pathname, names a file or directory by giving its location in a filesystem tree. Its spelling depends on the operating system: Linux and macOS use `/` between components and a single `/` root; Windows paths commonly use `\` and drive roots such as `C:\`. section 12.2

An absolute path starts from a root. A relative path is interpreted from the current working directory: `open('myfile', 'r')`, for example, looks for `myfile` there. `.` denotes the current directory and `..` its parent. Changing the working directory with `os.chdir()` differs from constructing a `Path` for another location. section 12.2 section 13.1 section 12.2.6 section 12.2.3

Use Python's path operations instead of manually inserting separators:

• `os.path.join('bin', 'utils', 'disktools')` combines components according to the operating system's conventions. section 12.7
• `Path('bin') / 'utils' / 'disktools'` constructs a path object. `joinpath()` is another way to add components. section 12.2.5
• Inspect a `Path` with `.parts`, `.name`, `.parent`, or `.suffix` when you need its components, final name, parent, or extension. section 12.2.5

a_path = Path('some', 'directory', 'path.jpg')
a_path.name
 
'path.jpg'
 
print(a_path.parent)
 
some/directory
 
a_path.suffix
 
'.jpg'

A short path example shows how `name`, `parent`, and `suffix` separate `some/directory/path.jpg` without parsing its string by hand. section 12.2.5

A path identifies a location; check the filesystem before assuming what is there:

• `os.path.exists(path)` tests whether anything exists there; `os.path.isfile(path)` and `os.path.isdir(path)` distinguish files from directories. `Path` provides corresponding methods. section 12.3 section 12.7
• `glob.glob()` finds matching names; `Path.glob()` returns matching path objects. `Path.iterdir()` likewise yields paths rather than a list of name strings. section 12.4 section 12.4.1

Paths also serve as targets for operations: `rename()` can move a file by giving it a path in another directory, while `mkdir()` creates a directory. `Path.mkdir(parents=True)` can create missing intermediate directories. `unlink()` removes a file, not a directory; `rmdir()` removes only an empty directory. section 12.4.1

import datetime
import pathlib
 
FILE_PATTERN = "*.txt"                                        #1
ARCHIVE = "archive"
 
def main():
    
    date_string = datetime.date.today().strftime("%Y-%m-%d")  #2
 
    cur_path = pathlib.Path(".")
    archive_path = cur_path.joinpath(ARCHIVE)       
    archive_path.mkdir(exist_ok=True)                         #3
 
    paths = cur_path.glob(FILE_PATTERN)
 
    for path in paths:
        new_filename = f"{path.stem}_{date_string}{path.suffix}"
        new_path = archive_path.joinpath(
                                         new_filename)        #4
        path.rename(new_path)                                 #5
 
if __name__ == '__main__':
     main()

A file-archiving script finds matching `.txt` paths, uses each path's stem and suffix to form a dated name, creates the archive directory, and renames each file into it. section 20.2

For file contents, pass a pathname to `open()` to obtain a file object, or use a `Path` object's text and binary read/write methods. The `Path` write methods replace existing content rather than append to it. section 13.1 section 13.5