zipfile

The zipfile module reads and writes ZIP archives. It supports both reading existing ZIP files and creating new ones, with optional compression. ZIP files are the standard archive format on Windows and widely used for distributing packaged software and bundled files.

Opening Archives

Reading an existing archive

Use ZipFile with mode ‘r’ to read an existing archive:

import zipfile

with zipfile.ZipFile('archive.zip', 'r') as zf:
    print(zf.namelist())
    # ['file1.txt', 'file2.txt', 'subdir/']
    
    # Read a specific file
    content = zf.read('file1.txt')
    print(content)

Creating a new archive

Use mode ‘w’ to create a new archive:

import zipfile

with zipfile.ZipFile('new.zip', 'w') as zf:
    # Add a file from disk
    zf.write('source.txt', 'destination.txt')
    
    # Add string content directly
    zf.writestr('hello.txt', 'Hello, world!')

ZipFile Class

The ZipFile class is the primary interface for working with ZIP archives.

Parameters

Parameter	Type	Default	Description
file	str or Path or file-like	—	Path to the ZIP file or a file-like object
mode	str	’r’	Mode: ‘r’ read, ‘w’ create, ‘a’ append
compression	int	ZIP_STORED	Compression method: ZIP_STORED, ZIP_DEFLATED, ZIP_BZIP2, ZIP_LZMA
compresslevel	int	-1	Compression level (1-9 for DEFLATED, 1-9 for BZIP2, 0-9 for LZMA)

ZipFile Methods

Method	Description
write()	Add a file to the archive
writestr()	Write data directly (string or bytes)
extractall()	Extract all files
extract()	Extract a single file
namelist()	List all file names
infolist()	List all ZipInfo objects
getinfo()	Get ZipInfo for a specific file
read()	Read file contents as bytes
close()	Close the archive

ZipInfo Class

The ZipInfo class represents a single member in a ZIP archive.

Parameters

Parameter	Type	Default	Description
filename	str	—	Name of the file in the archive
date_time	tuple	(1980,1,1,0,0,0)	Modification time as (year, month, day, hour, minute, second)

ZipInfo Attributes

Attribute	Type	Description
filename	str	Name of the file in the archive
date_time	tuple	Modification time
compress_type	int	Compression method used
file_size	int	Uncompressed size in bytes
compress_size	int	Compressed size in bytes
CRC	int	CRC-32 checksum
external_attr	int	External file attributes

Examples

Reading and extracting files

import zipfile
import os

with zipfile.ZipFile('data.zip', 'r') as zf:
    # List all files
    for name in zf.namelist():
        info = zf.getinfo(name)
        print(f"{name}: {info.file_size} bytes")
    
    # Extract everything
    zf.extractall('output_dir')
    
    # Extract a specific file
    zf.extract('specific.txt', 'output_dir')

Creating a compressed archive

import zipfile

with zipfile.ZipFile('backup.zip', 'w', zipfile.ZIP_DEFLATED) as zf:
    # Add multiple files
    for filename in ['file1.txt', 'file2.txt', 'file3.txt']:
        zf.write(filename)
    
    # Add with custom ZipInfo
    info = zipfile.ZipInfo('custom.txt')
    info.date_time = (2024, 1, 15, 10, 30, 0)
    zf.writestr(info, 'Content with custom metadata')

Common Patterns

List contents with details

import zipfile
from datetime import datetime

with zipfile.ZipFile('archive.zip', 'r') as zf:
    for info in zf.infolist():
        dt = datetime(*info.date_time)
        print(f"{info.filename:30} {info.file_size:>8} {dt}")

Selective extraction

import zipfile

with zipfile.ZipFile('archive.zip', 'r') as zf:
    # Extract only .txt files
    for member in zf.namelist():
        if member.endswith('.txt'):
            zf.extract(member, 'text_files/')

Create archive from directory

import zipfile
import os

def zip_directory(source_dir, output_path):
    with zipfile.ZipFile(output_path, 'w', zipfile.ZIP_DEFLATED) as zf:
        for root, dirs, files in os.walk(source_dir):
            for file in files:
                file_path = os.path.join(root, file)
                arcname = os.path.relpath(file_path, source_dir)
                zf.write(file_path, arcname)

Errors

Common exceptions

Exception	When it occurs
BadZipFile	File is not a valid ZIP archive or is corrupted
LargeZipFile	ZIP file exceeds 2GB (use ZIP64 format)
PasswordRequired	Attempting to read an encrypted archive without password
ZipShortRead	Unexpected end of file while reading

See Also

• os module
• os.path
• pathlib