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📘 NAME

bz2 - Interface to the libbzip2 compression library.

🚀 Quick Reference

Use Case	Command	Description
Compress a block of data	bz2.compress(data, compresslevel=9)	One-shot compression of bytes
Decompress a block of data	bz2.decompress(data)	One-shot decompression of bytes
Open a bzip2 file (binary or text mode)	bz2.open(filename, mode='rb', compresslevel=9)	Returns a file-like object
Read/write files transparently	with BZ2File('file.bz2', 'r') as f:	File interface for bzip2
Compress incrementally	compressor = BZ2Compressor(); compressor.compress(data); compressor.flush()	Incremental compression
Decompress incrementally	decompressor = BZ2Decompressor(); decompressor.decompress(data)	Incremental decompression

📂 MODULE REFERENCE

https://docs.python.org/3.10/library/bz2.html

The following documentation is automatically generated from the Python source files. It may be incomplete, incorrect or include features that are considered implementation detail and may vary between Python implementations. When in doubt, consult the module reference at the location listed above.

📝 DESCRIPTION

This module provides a file interface, classes for incremental (de)compression, and functions for one-shot (de)compression.

📦 CLASSES

_compression.BaseStream(io.BufferedIOBase)
    BZ2File
builtins.object
    _bz2.BZ2Compressor
    _bz2.BZ2Decompressor

🔧 class BZ2Compressor

class BZ2Compressor(builtins.object)
 |  BZ2Compressor(compresslevel=9, /)
 |
 |  Create a compressor object for compressing data incrementally.
 |
 |    compresslevel
 |      Compression level, as a number between 1 and 9.
 |
 |  For one-shot compression, use the compress() function instead.

Methods defined here:

• __init__(self, /, *args, **kwargs) — Initialize self. See help(type(self)) for accurate signature.
• compress(self, data, /) — Provide data to the compressor object. Returns a chunk of compressed data if possible, or b'' otherwise. When you have finished providing data to the compressor, call the flush() method to finish the compression process.
• flush(self, /) — Finish the compression process. Returns the compressed data left in internal buffers. The compressor object may not be used after this method is called.

Static methods defined here:

• __new__(*args, **kwargs) from builtins.type — Create and return a new object. See help(type) for accurate signature.

🔧 class BZ2Decompressor

class BZ2Decompressor(builtins.object)
 |  Create a decompressor object for decompressing data incrementally.
 |
 |  For one-shot decompression, use the decompress() function instead.

Methods defined here:

• __init__(self, /, *args, **kwargs) — Initialize self. See help(type(self)) for accurate signature.
• decompress(self, /, data, max_length=-1) — Decompress data, returning uncompressed data as bytes. If max_length is nonnegative, returns at most max_length bytes of decompressed data. If this limit is reached and further output can be produced, self.needs_input will be set to False. In this case, the next call to decompress() may provide data as b'' to obtain more of the output. If all of the input data was decompressed and returned (either because this was less than max_length bytes, or because max_length was negative), self.needs_input will be set to True. Attempting to decompress data after the end of stream is reached raises an EOFError. Any data found after the end of the stream is ignored and saved in the unused_data attribute.

Static methods defined here:

• __new__(*args, **kwargs) from builtins.type — Create and return a new object. See help(type) for accurate signature.

Data descriptors defined here:

• eof — True if the end-of-stream marker has been reached.
• needs_input — True if more input is needed before more decompressed data can be produced.
• unused_data — Data found after the end of the compressed stream.

📁 class BZ2File

class BZ2File(_compression.BaseStream)
 |  BZ2File(filename, mode='r', *, compresslevel=9)
 |
 |  A file object providing transparent bzip2 (de)compression.
 |
 |  A BZ2File can act as a wrapper for an existing file object, or refer
 |  directly to a named file on disk.
 |
 |  Note that BZ2File provides a *binary* file interface - data read is
 |  returned as bytes, and data to be written should be given as bytes.

Method resolution order:

BZ2File
_compression.BaseStream
io.BufferedIOBase
_io._BufferedIOBase
io.IOBase
_io._IOBase
builtins.object

Methods defined here:

• __init__(self, filename, mode='r', *, compresslevel=9) — Open a bzip2-compressed file. If filename is a str, bytes, or PathLike object, it gives the name of the file to be opened. Otherwise, it should be a file object, which will be used to read or write the compressed data. mode can be 'r' for reading (default), 'w' for (over)writing, 'x' for creating exclusively, or 'a' for appending. These can equivalently be given as 'rb', 'wb', 'xb', and 'ab'. If mode is 'w', 'x' or 'a', compresslevel can be a number between 1 and 9 specifying the level of compression: 1 produces the least compression, and 9 (default) produces the most compression. If mode is 'r', the input file may be the concatenation of multiple compressed streams.
• close(self) — Flush and close the file. May be called more than once without error. Once the file is closed, any other operation on it will raise a ValueError.
• fileno(self) — Return the file descriptor for the underlying file.
• peek(self, n=0) — Return buffered data without advancing the file position. Always returns at least one byte of data, unless at EOF. The exact number of bytes returned is unspecified.
• read(self, size=-1) — Read up to size uncompressed bytes from the file. If size is negative or omitted, read until EOF is reached. Returns b'' if the file is already at EOF.
• read1(self, size=-1) — Read up to size uncompressed bytes, while trying to avoid making multiple reads from the underlying stream. Reads up to a buffer's worth of data if size is negative. Returns b'' if the file is at EOF.
• readable(self) — Return whether the file was opened for reading.
• readinto(self, b) — Read bytes into b. Returns the number of bytes read (0 for EOF).
• readline(self, size=-1) — Read a line of uncompressed bytes from the file. The terminating newline (if present) is retained. If size is non-negative, no more than size bytes will be read (in which case the line may be incomplete). Returns b'' if already at EOF.
• readlines(self, size=-1) — Read a list of lines of uncompressed bytes from the file. size can be specified to control the number of lines read: no further lines will be read once the total size of the lines read so far equals or exceeds size.
• seek(self, offset, whence=0) — Change the file position. The new position is specified by offset, relative to the position indicated by whence. Values for whence are: 0: start of stream (default); offset must not be negative; 1: current stream position; 2: end of stream; offset must not be positive. Returns the new file position. Note that seeking is emulated, so depending on the parameters, this operation may be extremely slow.
• seekable(self) — Return whether the file supports seeking.
• tell(self) — Return the current file position.
• writable(self) — Return whether the file was opened for writing.
• write(self, data) — Write a byte string to the file. Returns the number of uncompressed bytes written, which is always the length of data in bytes. Note that due to buffering, the file on disk may not reflect the data written until close() is called.
• writelines(self, seq) — Write a sequence of byte strings to the file. Returns the number of uncompressed bytes written. seq can be any iterable yielding byte strings. Line separators are not added between the written byte strings.

Readonly properties defined here:

• closed — True if this file is closed.

Data and other attributes defined here:

• __abstractmethods__ = frozenset()

Methods inherited from _io._BufferedIOBase:

• detach(self, /) — Disconnect this buffer from its underlying raw stream and return it. After the raw stream has been detached, the buffer is in an unusable state.
• readinto1(self, buffer, /)

Methods inherited from _io._IOBase:

• __del__(...)
• __enter__(...)
• __exit__(...)
• __iter__(self, /) — Implement iter(self).
• __next__(self, /) — Implement next(self).
• flush(self, /) — Flush write buffers, if applicable. This is not implemented for read-only and non-blocking streams.
• isatty(self, /) — Return whether this is an 'interactive' stream. Return False if it can't be determined.
• truncate(...) — Truncate file to size bytes. File pointer is left unchanged. Size defaults to the current IO position as reported by tell(). Returns the new size.

Static methods inherited from _io._IOBase:

• __new__(*args, **kwargs) from builtins.type — Create and return a new object. See help(type) for accurate signature.

Data descriptors inherited from _io._IOBase:

• __dict__

⚙️ FUNCTIONS

📌 compress

compress(data, compresslevel=9)
    Compress a block of data.

    compresslevel, if given, must be a number between 1 and 9.

    For incremental compression, use a BZ2Compressor object instead.

📌 decompress

decompress(data)
    Decompress a block of data.

    For incremental decompression, use a BZ2Decompressor object instead.

📌 open

open(filename, mode='rb', compresslevel=9, encoding=None, errors=None, newline=None)
    Open a bzip2-compressed file in binary or text mode.

    The filename argument can be an actual filename (a str, bytes, or
    PathLike object), or an existing file object to read from or write
    to.

    The mode argument can be "r", "rb", "w", "wb", "x", "xb", "a" or
    "ab" for binary mode, or "rt", "wt", "xt" or "at" for text mode.
    The default mode is "rb", and the default compresslevel is 9.

    For binary mode, this function is equivalent to the BZ2File
    constructor: BZ2File(filename, mode, compresslevel). In this case,
    the encoding, errors and newline arguments must not be provided.

    For text mode, a BZ2File object is created, and wrapped in an
    io.TextIOWrapper instance with the specified encoding, error
    handling behavior, and line ending(s).

📊 DATA

__all__ = ['BZ2File', 'BZ2Compressor', 'BZ2Decompressor', 'open', 'com...

👤 AUTHOR

Nadeem Vawda <nadeem.vawda AT gmail.com>

📁 FILE

/usr/lib/python3.10/bz2.py

📘 NAME 🚀 Quick Reference 📂 MODULE REFERENCE 📝 DESCRIPTION 📦 CLASSES ⚙️ FUNCTIONS 📊 DATA 👤 AUTHOR 📁 FILE