Just a reminder to whom google this error and come here.
Let's say I get this error:
$ python3 example.py
Traceback (most recent call last):
File "example.py", line 7, in <module>
import aalib
ModuleNotFoundError: No module named 'aalib'
Since it mentions aalib
, I was thought to try aalib
:
$ python3.8 -m pip install aalib
ERROR: Could not find a version that satisfies the requirement aalib (from versions: none)
ERROR: No matching distribution found for aalib
But it actually wrong package name, ensure pip search
(service disabled at the time of writing), or google, or search on pypi site to get the accurate package name:

Then install successfully:
$ python3.8 -m pip install python-aalib
Collecting python-aalib
Downloading python-aalib-0.3.2.tar.gz (14 kB)
...
As pip --help
stated:
$ python3.8 -m pip
...
-v,
To have a systematic way to figure out the root causes instead of rely on luck, you can append -vvv
option of pip
command to see details, e.g.:
$ python3.8 -u -m pip install aalib -vvv
User install by explicit request
Created temporary directory: /tmp/pip-ephem-wheel-cache-b3ghm9eb
Created temporary directory: /tmp/pip-req-tracker-ygwnj94r
Initialized build tracking at /tmp/pip-req-tracker-ygwnj94r
Created build tracker: /tmp/pip-req-tracker-ygwnj94r
Entered build tracker: /tmp/pip-req-tracker-ygwnj94r
Created temporary directory: /tmp/pip-install-jfurrdbb
1 location(s) to search for versions of aalib:
* https://pypi.org/simple/aalib/
Fetching project page and analyzing links: https://pypi.org/simple/aalib/
Getting page https://pypi.org/simple/aalib/
Found index url https://pypi.org/simple
Getting credentials from keyring for https://pypi.org/simple
Getting credentials from keyring for pypi.org
Looking up "https://pypi.org/simple/aalib/" in the cache
Request header has "max_age" as 0, cache bypassed
Starting new HTTPS connection (1): pypi.org:443
https://pypi.org:443 "GET /simple/aalib/ HTTP/1.1" 404 13
[hole] Status code 404 not in (200, 203, 300, 301)
Could not fetch URL https://pypi.org/simple/aalib/: 404 Client Error: Not Found for url: https://pypi.org/simple/aalib/ - skipping
Given no hashes to check 0 links for project 'aalib': discarding no candidates
ERROR: Could not find a version that satisfies the requirement aalib (from versions: none)
Cleaning up...
Removed build tracker: '/tmp/pip-req-tracker-ygwnj94r'
ERROR: No matching distribution found for aalib
Exception information:
Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/pip/_internal/cli/base_command.py", line 186, in _main
status = self.run(options, args)
File "/usr/lib/python3/dist-packages/pip/_internal/commands/install.py", line 357, in run
resolver.resolve(requirement_set)
File "/usr/lib/python3/dist-packages/pip/_internal/legacy_resolve.py", line 177, in resolve
discovered_reqs.extend(self._resolve_one(requirement_set, req))
File "/usr/lib/python3/dist-packages/pip/_internal/legacy_resolve.py", line 333, in _resolve_one
abstract_dist = self._get_abstract_dist_for(req_to_install)
File "/usr/lib/python3/dist-packages/pip/_internal/legacy_resolve.py", line 281, in _get_abstract_dist_for
req.populate_link(self.finder, upgrade_allowed, require_hashes)
File "/usr/lib/python3/dist-packages/pip/_internal/req/req_install.py", line 249, in populate_link
self.link = finder.find_requirement(self, upgrade)
File "/usr/lib/python3/dist-packages/pip/_internal/index/package_finder.py", line 926, in find_requirement
raise DistributionNotFound(
pip._internal.exceptions.DistributionNotFound: No matching distribution found for aalib
From above log, there is pretty obvious the URL https://pypi.org/simple/aalib/
404 not found. Then you can guess the possible reasons which cause that 404, i.e. wrong package name. Another thing is I can modify relevant python files of pip modules to further debug with above log. To edit .whl
file, you can use wheel
command to unpack
and pack
.