pathlib - Object-Oriented Filesystem Paths

The pathlib module provides classes for working with filesystem paths in an object-oriented way. It’s the modern replacement for many os.path operations.

Module Import

from pathlib import Path

Creating Path Objects

Path() - Platform-Specific Path

from pathlib import Path

# Current directory
p = Path('.')

# Specific file
p = Path('data.txt')

# Nested path
p = Path('folder/subfolder/file.txt')

# Multiple components
p = Path('folder', 'subfolder', 'file.txt')

# From home directory
p = Path.home() / 'documents' / 'file.txt'

# Current working directory
p = Path.cwd()

Path Operators

Use / operator to join paths:

from pathlib import Path

base = Path('/home/user')
path = base / 'documents' / 'file.txt'
print(path)  # /home/user/documents/file.txt

# Can mix strings and Path objects
path = Path('folder') / 'subfolder' / 'file.txt'

# Right division
path = 'folder' / Path('subfolder') / 'file.txt'

Path Properties

Path Components

from pathlib import Path

path = Path('/home/user/documents/file.txt')

# Parts
print(path.parts)  # ('/', 'home', 'user', 'documents', 'file.txt')

# Name (filename with extension)
print(path.name)  # 'file.txt'

# Stem (filename without extension)
print(path.stem)  # 'file'

# Suffix (extension)
print(path.suffix)  # '.txt'

# Multiple extensions
path = Path('archive.tar.gz')
print(path.suffixes)  # ['.tar', '.gz']

# Parent directory
print(path.parent)  # /home/user/documents

# All parents
for parent in path.parents:
    print(parent)
# /home/user/documents
# /home/user
# /home
# /

Path Types

from pathlib import Path

path = Path('/home/user/file.txt')

# Drive letter (Windows: 'C:', Unix: '')
print(path.drive)

# Root (Unix: '/', Windows: '\\')
print(path.root)

# Anchor (drive + root)
print(path.anchor)

# Check if absolute
if path.is_absolute():
    print("Absolute path")

File Operations

Reading Files

from pathlib import Path

path = Path('data.txt')

# Read entire file as string
content = path.read_text(encoding='utf-8')

# Read as bytes
data = path.read_bytes()

# Read lines
lines = path.read_text().splitlines()

# Iterate over lines
for line in path.open():
    print(line.strip())

Writing Files

from pathlib import Path

path = Path('output.txt')

# Write string
path.write_text('Hello, World!', encoding='utf-8')

# Write bytes
path.write_bytes(b'Binary data')

# Append to file
with path.open('a') as f:
    f.write('Appended line\n')

File Information

from pathlib import Path
from datetime import datetime

path = Path('file.txt')

# Check existence
if path.exists():
    print("File exists")

# Check type
if path.is_file():
    print("It's a file")

if path.is_dir():
    print("It's a directory")

if path.is_symlink():
    print("It's a symbolic link")

# Get stats
stats = path.stat()
print(f"Size: {stats.st_size} bytes")
print(f"Modified: {datetime.fromtimestamp(stats.st_mtime)}")

# File size
size = path.stat().st_size
print(f"Size: {size / 1024:.2f} KB")

Directory Operations

Listing Contents

from pathlib import Path

path = Path('.')

# List all items
for item in path.iterdir():
    print(item)

# Filter files
for file in path.iterdir():
    if file.is_file():
        print(file.name)

# Filter by extension
for py_file in path.glob('*.py'):
    print(py_file)

# Recursive search
for py_file in path.rglob('*.py'):
    print(py_file)

# Using glob patterns
for item in path.glob('**/*.txt'):
    print(item)

Creating and Removing Directories

from pathlib import Path

# Create directory
Path('new_folder').mkdir()

# Create nested directories
Path('path/to/nested/folder').mkdir(parents=True, exist_ok=True)

# Remove empty directory
Path('empty_folder').rmdir()

# Remove file
Path('file.txt').unlink()

# Remove file if exists
path = Path('file.txt')
if path.exists():
    path.unlink()

# Or with missing_ok (Python 3.8+)
path.unlink(missing_ok=True)

Path Manipulation

Joining Paths

from pathlib import Path

# Using / operator
base = Path('/home/user')
path = base / 'documents' / 'file.txt'

# Using joinpath method
path = base.joinpath('documents', 'file.txt')

Changing Path Components

from pathlib import Path

path = Path('/home/user/documents/file.txt')

# Change filename
new_path = path.with_name('newfile.txt')
print(new_path)  # /home/user/documents/newfile.txt

# Change extension
new_path = path.with_suffix('.md')
print(new_path)  # /home/user/documents/file.md

# Change stem (filename without extension)
new_path = path.with_stem('newfile')
print(new_path)  # /home/user/documents/newfile.txt

Resolving Paths

from pathlib import Path

path = Path('relative/path/file.txt')

# Get absolute path
absolute = path.resolve()
print(absolute)

# Expand user home directory
path = Path('~/documents')
expanded = path.expanduser()
print(expanded)  # /home/user/documents

# Make relative to another path
path = Path('/home/user/documents/file.txt')
base = Path('/home/user')
relative = path.relative_to(base)
print(relative)  # documents/file.txt

File Operations

Renaming and Moving

from pathlib import Path

# Rename file
old_path = Path('old_name.txt')
new_path = Path('new_name.txt')
old_path.rename(new_path)

# Move file
source = Path('file.txt')
dest = Path('folder/file.txt')
source.rename(dest)

# Replace (atomic on some platforms)
source.replace(dest)

Copying Files

from pathlib import Path
import shutil

source = Path('source.txt')
dest = Path('dest.txt')

# pathlib doesn't have copy, use shutil
shutil.copy(source, dest)

# Copy with metadata
shutil.copy2(source, dest)

# Copy directory
shutil.copytree(Path('source_dir'), Path('dest_dir'))

Permissions

from pathlib import Path
import stat

path = Path('file.txt')

# Change permissions
path.chmod(0o644)  # rw-r--r--

# Make executable
path.chmod(path.stat().st_mode | stat.S_IXUSR)

# Get current permissions
mode = path.stat().st_mode
print(oct(stat.S_IMODE(mode)))  # e.g., '0o644'

Special Methods

Path Matching

from pathlib import Path

path = Path('/home/user/documents/file.txt')

# Match pattern
if path.match('*.txt'):
    print("Text file")

if path.match('**/documents/*.txt'):
    print("Text file in documents folder")

Symbolic Links

from pathlib import Path

target = Path('target.txt')
link = Path('link.txt')

# Create symbolic link
link.symlink_to(target)

# Read link target
if link.is_symlink():
    target = link.readlink()
    print(f"Link points to: {target}")

# Resolve symlinks
real_path = link.resolve()

Practical Examples

Find All Files with Extension

from pathlib import Path

def find_files(directory, pattern):
    """Find all files matching pattern recursively"""
    return list(Path(directory).rglob(pattern))

# Usage
python_files = find_files('.', '*.py')
for file in python_files:
    print(file)

Calculate Directory Size

from pathlib import Path

def get_directory_size(directory):
    """Calculate total size of directory in bytes"""
    total = 0
    for item in Path(directory).rglob('*'):
        if item.is_file():
            total += item.stat().st_size
    return total

# Usage
size = get_directory_size('.')
print(f"Directory size: {size / (1024**2):.2f} MB")

Backup Files with Timestamp

from pathlib import Path
from datetime import datetime
import shutil

def backup_file(filepath):
    """Create timestamped backup of file"""
    path = Path(filepath)
    if not path.exists():
        return None
    
    timestamp = datetime.now().strftime('%Y%m%d_%H%M%S')
    backup_path = path.with_stem(f"{path.stem}_{timestamp}")
    
    shutil.copy2(path, backup_path)
    return backup_path

# Usage
backup = backup_file('important.txt')
print(f"Backup created: {backup}")

Clean Up Old Files

from pathlib import Path
from datetime import datetime, timedelta

def clean_old_files(directory, days=30, pattern='*'):
    """Remove files older than specified days"""
    cutoff = datetime.now() - timedelta(days=days)
    removed = []
    
    for file in Path(directory).glob(pattern):
        if file.is_file():
            mtime = datetime.fromtimestamp(file.stat().st_mtime)
            if mtime < cutoff:
                file.unlink()
                removed.append(file)
    
    return removed

# Usage
removed = clean_old_files('/tmp', days=7, pattern='*.tmp')
print(f"Removed {len(removed)} files")

Process All Files in Directory

from pathlib import Path

def process_files(directory, extension='.txt'):
    """Process all files with given extension"""
    for file in Path(directory).rglob(f'*{extension}'):
        if file.is_file():
            content = file.read_text()
            # Process content
            lines = len(content.splitlines())
            words = len(content.split())
            print(f"{file.name}: {lines} lines, {words} words")

# Usage
process_files('.', '.py')

Path Types

Pure Paths (No I/O)

from pathlib import PurePath, PurePosixPath, PureWindowsPath

# Platform-independent path manipulation
path = PurePath('/home/user/file.txt')

# Force Unix-style paths
posix_path = PurePosixPath('/home/user/file.txt')

# Force Windows-style paths  
win_path = PureWindowsPath('C:/Users/user/file.txt')

# Pure paths don't access filesystem
path = PurePath('nonexistent.txt')
print(path.name)  # Works even if file doesn't exist

Concrete Paths (With I/O)

from pathlib import Path, PosixPath, WindowsPath

# Platform-specific (recommended)
path = Path('file.txt')

# Force POSIX (only works on POSIX systems)
# posix_path = PosixPath('file.txt')

# Force Windows (only works on Windows)
# win_path = WindowsPath('file.txt')

Best Practices

Use pathlib instead of os.path for new code:

# Modern
from pathlib import Path
path = Path('folder') / 'file.txt'
if path.exists():
    content = path.read_text()

# Old style
import os
path = os.path.join('folder', 'file.txt')
if os.path.exists(path):
    with open(path) as f:
        content = f.read()

Use missing_ok=True when deleting:

# Avoid errors if file doesn't exist
Path('file.txt').unlink(missing_ok=True)

# Instead of
path = Path('file.txt')
if path.exists():
    path.unlink()

Always use parents=True when creating nested directories:

Path('path/to/nested/folder').mkdir(parents=True, exist_ok=True)

Migration from os.path

os.path	pathlib
`os.path.join(a, b)`	`Path(a) / b`
`os.path.exists(path)`	`Path(path).exists()`
`os.path.isfile(path)`	`Path(path).is_file()`
`os.path.isdir(path)`	`Path(path).is_dir()`
`os.path.basename(path)`	`Path(path).name`
`os.path.dirname(path)`	`Path(path).parent`
`os.path.splitext(path)`	`Path(path).stem`, `Path(path).suffix`
`os.path.abspath(path)`	`Path(path).resolve()`
`os.getcwd()`	`Path.cwd()`
`os.path.expanduser('~')`	`Path.home()`

os

Operating system interfaces

shutil

High-level file operations

glob

Unix-style pathname patterns

tempfile

Temporary files

​Module Import

​Creating Path Objects

​Path() - Platform-Specific Path

​Path Operators

​Path Properties

​Path Components

​Path Types

​File Operations

​Reading Files

​Writing Files

​File Information

​Directory Operations

​Listing Contents

​Creating and Removing Directories

​Path Manipulation

​Joining Paths

​Changing Path Components

​Resolving Paths

​File Operations

​Renaming and Moving

​Copying Files

​Permissions

​Special Methods

​Path Matching

​Symbolic Links

​Practical Examples

​Find All Files with Extension

​Calculate Directory Size

​Backup Files with Timestamp

​Clean Up Old Files

​Process All Files in Directory

​Path Types

​Pure Paths (No I/O)

​Concrete Paths (With I/O)

​Best Practices

​Migration from os.path

​Related Modules

os

shutil

glob

tempfile

Module Import

Creating Path Objects

Path() - Platform-Specific Path

Path Operators

Path Properties

Path Components

Path Types

File Operations

Reading Files

Writing Files

File Information

Directory Operations

Listing Contents

Creating and Removing Directories

Path Manipulation

Joining Paths

Changing Path Components

Resolving Paths

File Operations

Renaming and Moving

Copying Files

Permissions

Special Methods

Path Matching

Symbolic Links

Practical Examples

Find All Files with Extension

Calculate Directory Size

Backup Files with Timestamp

Clean Up Old Files

Process All Files in Directory

Path Types

Pure Paths (No I/O)

Concrete Paths (With I/O)

Best Practices

Migration from os.path

Related Modules