Master Python File Compression: Zip, Tar.gz, RAR, and 7z Made Easy

Introduction

In daily work, Python is often used to process text files and compressed archives.

Common Compression Formats

rar – widely used on Windows, typically handled with WinRAR.

tar – Linux packaging tool (no compression by itself).

gz – gzip, compresses a single file; combined with tar for tar.gz.

tgz – tar followed by gzip compression.

zip – can compress multiple files, similar algorithm to gzip.

7z – high‑efficiency format supported by 7‑Zip.

Working with ZIP Files

The zipfile module provides ZipFile for creating and reading zip archives and ZipInfo for file metadata.

import os
import zipfile

# Compression
def make_zip(source_dir, output_filename):
    zipf = zipfile.ZipFile(output_filename, 'w')
    pre_len = len(os.path.dirname(source_dir))
    for parent, dirnames, filenames in os.walk(source_dir):
        for filename in filenames:
            pathfile = os.path.join(parent, filename)
            arcname = pathfile[pre_len:].strip(os.path.sep)  # relative path
            zipf.write(pathfile, arcname)
    zipf.close()

# Decompression
def un_zip(file_name):
    """unzip zip file"""
    zip_file = zipfile.ZipFile(file_name)
    if os.path.isdir(file_name + "_files"):
        pass
    else:
        os.mkdir(file_name + "_files")
    for names in zip_file.namelist():
        zip_file.extract(names, file_name + "_files/")
    zip_file.close()

if __name__ == '__main__':
    make_zip(r"E:python_samplelibstest_tar_fileslibs", "test.zip")
    un_zip("test.zip")

Working with TAR.GZ Files

The tarfile module reads and writes tar archives, optionally compressed with gzip, bzip2, or lzma. The mode string follows the pattern filemode[:compression]. Common modes include: r or r:* – read with transparent compression (default). r: – read without compression. r:gz – read gzip‑compressed archive. r:bz2 – read bzip2‑compressed archive. r:xz – read lzma‑compressed archive. x – create an uncompressed tar archive. x:gz – create a gzip‑compressed tar archive. w – write uncompressed. w:gz – write gzip‑compressed.

Alternative stream modes use the | separator (e.g., r|gz for a gzip stream).

import os
import tarfile
import gzip

# Pack an entire directory into a .tar.gz file
def make_targz(output_filename, source_dir):
    with tarfile.open(output_filename, "w:gz") as tar:
        tar.add(source_dir, arcname=os.path.basename(source_dir))

# Pack files one by one (empty sub‑directories are skipped)
def make_targz_one_by_one(output_filename, source_dir):
    tar = tarfile.open(output_filename, "w:gz")
    for root, dir, files in os.walk(source_dir):
        for file in files:
            pathfile = os.path.join(root, file)
            tar.add(pathfile)
    tar.close()

# Decompress a .gz file
def un_gz(file_name):
    """ungz zip file"""
    f_name = file_name.replace('.gz', '')
    g_file = gzip.GzipFile(file_name)
    open(f_name, "wb+").write(g_file.read())
    g_file.close()

# Decompress a .tar archive
def un_tar(file_name):
    tar = tarfile.open(file_name)
    names = tar.getnames()
    if not os.path.isdir(file_name + "_files"):
        os.mkdir(file_name + "_files")
    for name in names:
        tar.extract(name, file_name + "_files/")
    tar.close()

if __name__ == '__main__':
    make_targz('test.tar.gz', "E:python_samplelibs")
    make_targz_one_by_one('test01.tgz', "E:python_samplelibs")
    un_gz('test.tar.gz')
    un_tar('test.tar')

Handling RAR Files

Python can extract .rar files using the rarfile library, but it requires the official unrar library.

Windows installation

Download UnRARDLL.exe from the RARLab website and install (default path is C:\Program Files (x86)\UnrarDLL).

Add an environment variable UNRAR_LIB_PATH pointing to UnRAR64.dll (64‑bit) or UnRAR.dll (32‑bit).

Run pip install unrar again.

Linux installation

Download the source rarlinux-6.0.0.tar.gz from RARLab.

Extract, compile, and install to produce libunrar.so.

Set UNRAR_LIB_PATH to the location of libunrar.so and run pip install unrar.

# cd /usr/local/src/
# wget https://www.rarlab.com/rar/unrarsrc-6.0.3.tar.gz
# tar zxvf unrarsrc-6.0.3.tar.gz
# cd unrar
# make lib
# make install-lib   # creates libunrar.so
# echo 'export UNRAR_LIB_PATH=/usr/lib/libunrar.so' >> /etc/profile
# source /etc/profile

import rarfile

def unrar(rar_file, dir_name):
    # rarfile needs unrar support; on Linux install via pip, on Windows add unrar.exe to PATH
    rarobj = rarfile.RarFile(rar_file.decode('utf-8'))
    rarobj.extractall(dir_name.decode('utf-8'))

Working with 7Z Files

The py7zr library handles .7z archives.

import py7zr

# Decompression
with py7zr.SevenZipFile("Archive.7z", 'r') as archive:
    archive.extractall(path="/tmp")

# Compression
with py7zr.SevenZipFile("Archive.7z", 'w') as archive:
    archive.writeall("target/")