How to unpack .rar file in Python?

Question

I have a problem in unpacking .rar files in Python. I am using macOS, with Anaconda Navigator and Spyder IDE. I have already installed unrar, pyunpack, py7zr, rarfile, patool packages. However, when I run this code:

import zipfile

import numpy as np
import pandas as pd
from rarfile import RarFile
import patoolib
from pyunpack import Archive

# Archive('aaa.rar').extractall(".")
patoolib.extract_archive('aaa.rar')

I get the error message:

PatoolError: could not find an executable program to extract format rar; candidates are (rar,unrar,7z),

and

File "/opt/anaconda3/lib/python3.7/site-packages/patoolib/__init__.py", line 684, in extract_archive
    return _extract_archive(archive, verbosity=verbosity, interactive=interactive, outdir=outdir, program=program)

  File "/opt/anaconda3/lib/python3.7/site-packages/patoolib/__init__.py", line 470, in _extract_archive
    program = find_archive_program(format, 'extract', program=program)

  File "/opt/anaconda3/lib/python3.7/site-packages/patoolib/__init__.py", line 336, in find_archive_program
    raise util.PatoolError("could not find an executable program to %s format %s; candidates are (%s)," % (command, format, ",".join(programs)))

Can somebody help me, please?

Answer 1

You can use rarfile module

import rarfile

rf = rarfile.RarFile("myarchive.rar")
for f in rf.infolist():
    print(f.filename, f.file_size)
    if f.filename == "README":
        print(rf.read(f))

Answer 2

The issue is that unrar (and other programs you've installed locally) are not findable by Anaconda from within an Anaconda environment. The solution is to install them within that environemtn.

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From within your Anaconda environment,

conda install unrar

will make unrar available, and make Python packages like patoolib that depend on it work.

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Conda also provides a conda package for handling .rar files, which can be installed with

conda install -c conda-forge 7zip

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More information on Conda environments can be found here. In particular they say one of the benefits of a Conda environment is that it "Manages non-Python dependencies (R, Perl, arbitrary executables).", of which unrar is an arbitrary executable.