DEV Community: Lam Nguyen

Relative imports in Python 3

Lam Nguyen — Thu, 18 Feb 2021 11:24:15 +0000

Relative imports in Python 3

Jun 7 '13 Comments: 13 Answers: 18

I want to import a function from another file in the same directory.

Sometimes it works for me with from .mymodule import myfunction but sometimes I get a:

SystemError: Parent module '' not loaded, cannot perform relative import

Sometimes it works with from mymodule import myfunction, but sometimes I…

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Answer: How to set the python type hinting for a dictionary variable?

Lam Nguyen — Mon, 01 Feb 2021 04:00:28 +0000

answer re: How to set the python type hinting for a dictionary variable?

Oct 1 '18

Dict takes two "arguments", the type of its keys and the type of its values. For a dict that maps strings to integers, use

def doSomething(value: Dict[str, int]):

The documentation could probably be a little more explicit, though.

</p>

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from typing import Dict

def doSomething(Some_Dict: Dict[str, SomeObject]):

then voila! your IDE will suggest the members of each value (SomeObject) in the dictionary!

Answer: Error response from daemon: service endpoint with name

Lam Nguyen — Fri, 20 Nov 2020 08:25:36 +0000

answer re: Error response from daemon: service endpoint with name

May 2 '17

Just in case someone else needs this. As @Jmons pointed out it was a weird networking issue. So I solved this by forcing a removal

docker network disconnect --force bridge qc.T8

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Answer: What does functools.wraps do?

Lam Nguyen — Fri, 30 Oct 2020 08:52:12 +0000

answer re: What does functools.wraps do?

Nov 21 '08

1130

When you use a decorator, you're replacing one function with another. In other words, if you have a decorator

def logged(func):
    def with_logging(*args, **kwargs):
        print(func.__name__ + " was called")
        return func(*args, **kwargs)
    return with_logging

then when you say

@logged
def f(x):
   """does some math"""
   return x + x * x

…

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Answer: store results ThreadPoolExecutor

Lam Nguyen — Thu, 29 Oct 2020 03:43:01 +0000

answer re: store results ThreadPoolExecutor

Aug 29 '18

When you call future.result(), that blocks until the value is ready. So, you’re not getting any benefits out of parallelism here—you start one task, wait for it to finish, start another, wait for it to finish, and so on.

Of course your example won’t benefit from threading in the…

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The most simple way to set up sshfs with autofs!

Lam Nguyen — Mon, 26 Oct 2020 10:08:49 +0000

https://www.ullright.org/ullWiki/show/sshfs-mount

lazy umount

Lam Nguyen — Fri, 23 Oct 2020 10:18:51 +0000

https://superuser.com/a/943452/1010403

Answer: How can I sort a dictionary by key?

Lam Nguyen — Thu, 01 Oct 2020 09:45:19 +0000

answer re: How can I sort a dictionary by key?

Oct 30 '17

179

For CPython/PyPy 3.6, and any Python 3.7 or higher, this is easily done with:

>>> d = {2:3, 1:89, 4:5, 3:0}
>>> dict(sorted(d.items()))
{1: 89, 2: 3, 3: 0, 4: 5}

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Answer: import module from string variable

Lam Nguyen — Wed, 30 Sep 2020 07:25:07 +0000

answer re: import module from string variable

Feb 3 '20

Apart from using the importlib one can also use exec method to import a module from a string variable.

Here I am showing an example of importing the combinations method from itertools package using the exec method:

MODULES = [
    ['itertools','combinations'],
]

for ITEM in MODULES:
    import_str = "from {0}

…

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Answer: How to get reference to module by string name and call its method by string name?

Lam Nguyen — Wed, 30 Sep 2020 07:16:04 +0000

answer re: How to get reference to module by string name and call its method by string name?

Jun 17 '13

To get the module, you can use globals. To get the function, use getattr:

getattr(globals()[module_name], function_name)

Importing a module just binds the module object to a name in whatever namespace you import it in. In the usual case where you import at the top level of the module…

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https://docs.python.org/3/library/asyncio-eventloop.html#asyncio.loop.run_in_executor

Lam Nguyen — Tue, 29 Sep 2020 11:00:52 +0000

https://docs.python.org/3/library/ahttps://docs.python.org/3/library/asyncio-eventloop.html#asyncio.loop.run_in_executor

Answer: Can concurrent.futures.Future be converted to asyncio.Future?

Lam Nguyen — Tue, 29 Sep 2020 03:18:39 +0000

answer re: Can concurrent.futures.Future be converted to asyncio.Future?

Jan 31 '20

For the "concurrent future to asyncio future" part, here is an utility I use.

from typing import List, Any
from concurrent.futures.thread import ThreadPoolExecutor
import asyncio


class AsyncThreadPool(ThreadPoolExecutor):
    _futures: List[asyncio.Future]
    _loop: asyncio.AbstractEventLoop

    def __init__(self, max_workers=None):
        super().__init__(max_workers)
        self._futures = []

    def queue(self, fn):
        self._loop = asyncio.get_event_loop()
        fut = self._loop.create_future()
        self._futures.append(fut)
        self.submit(self._entry, fn,

…

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