Python requires a GIL. But Jython & IronPython don't. Why?

Why is it that you can run Jython and IronPython without the need for a GIL but Python (CPython) requires a GIL?

How is set() implemented?

I've seen people say that set objects in python have O(1) membership-checking. How are they implemented internally to allow this? What sort of data structure does it use? What other implications...

Python 3.3 source code setup: modules were not found: _lzma _sqlite3 _tkinter

I am trying to set up the compiled version of CPython, on Ubuntu 12.04, by following the python developer guide. Even after installing the dependent packages lzma and sqlite3, build fails...

Short-circuiting list comprehensions

On several occasions I've wanted python syntax for short-circuiting list comprehensions or generator expressions. Here is a simple list comprehension, and the equivalent for loop in...

How exactly is Python Bytecode Run in CPython?

I am trying to understand how Python works (because I use it all the time!). To my understanding, when you run something like python script.py, the script is converted to bytecode and then the...

Is OrderedDict a tree?

OrderedDict is a collection that preserves order of items (in which they were inserted). I do not think this can be achieved with hashtables (which regular dict uses I think) so are balanced trees...

How to use await in a python lambda

I'm trying to do something like this: mylist.sort(key=lambda x: await somefunction(x)) But I get this error: SyntaxError: 'await' outside async function Which makes sense because the lambda is...

Django says - No module named 'blog'

I am getting "ModuleNotFoundError: No module named 'blog'" error when add my blog app to the INSTALLED_APPS section of settings.py. I have determined that it has something to do with the way I...

conda update CondaHTTPError: HTTP None

Midway through running Conda Update --all, the update stalled. Multiple packages had been updated. Now, when I run conda update --all or conda update conda, I get this...

dyld: Library not loaded: @rpath/libreadline.6.2.dylib and @rpath/libintl.8.dylib

I just installed the new update on OSX because it kept popping up. Of course, it broke something. I can't access my R anymore. Took me forever to get my environment set up. I have all of my R...

Getting "ImportError: libXrender.so.1: cannot open shared object file" when importing OpenCV

I'm having trouble importing OpenCV. Environment: Python 3.6.1 Linux (HPC server) OpenCV 3.4.3.18 Error Description: I'm trying to import cv2 after a successful installation (Requirement already...

"No SSL support included in this python" Anaconda-python3-smtplib

I am using Anaconda environment with python 3.7 set up. I am trying to send a simple email via my gmail account using smtplib and I am getting "No SSL support included in this python" I do realize...

WEBP support not installed error with Pillow included in Anaconda

I have written a small code to open webp image in the Anaconda prompt. from PIL import Image im = Image.open('test.webp') It causes the following...

How to deal with "[Errno 122] Disk quota exceeded" problem when creating new environment by anaconda?

I am trying to create a new environment for Python through Anaconda. But the error keeps coming out saying : Solving environment: failed # >>>>>>>>>>>>>>>>>>>>>> ERROR REPORT...

How to redirect/render Pyodide output in browser?

I have recently come across the Pyodide project. I have built a little demo using Pyodide, but although I've spent a lot of time looking at the source, it is not obvious (yet) to me how to...

ArgumentError: argument 3: <class 'TypeError'>: wrong type

I'm testing kivy on win10 via nimiconda. Everytime when I run(press F5 on miniconda,the same as anaconda) the kivy code for the second time,the consel will throw "ArgumentError: argument 3: <class...

Python list.clear() time and space complexity?

I am writing a blogpost on Python list.clear() method where I also want to mention about the time and space complexity of the underlying algorithm. I expected the time complexity to be O(N),...

Unable to create v. environment for Python 2.17. Runtime error: failed to query python.exe

Please, help me to resolve this issue. I attempted to create virtual environment using pipenv --two and failure occured due to runtime error: failed to query python.exe. Here is a snippet of...

Using hash for identity on Python dataclasses

I have the following Filer entity (in the domain-driven design sense). from dataclasses import dataclass, field @dataclass class Address: street: str city: str state: str zipcode:...

How to call Rust async method from Python?

I want to use a Rust async method in Python. I'm trying to use PyO3 or rust-cpython. For example, for sync Rust functions, I can use, #[pyfunction] fn myfunc(a: String) -> PyResult<String> { ...

__str__ function of class ported from rust to python using pyo3 doesn't get used in print

I am using the pyo3 rust crate (version 0.11.1) in order to port rust code, into cpython (version 3.8.2) code. I have created a class called my_class and defined the following functions: new,...

Docker Compose - stuck on Sending Auth Config

I have a pretty straight forward app I'm building. I'm trying to go from a manual input command to using docker compose. I'm stuck in the build when using docker compose. It seems to work fine if...

How to colorise the Python repl

As we can see the difference between the images. In vim datatype and function are of different color. How can i bring color to my python repl. I want to do it by myself. Please suggest me, how...

PyVISA not listing USB instrument on Linux

I am trying to communicate with a LeCroy WaveRunner 640Zi oscilloscope from a Raspberry Pi, they are connected with a USB cable. I have already done this under Windows, but now I am not able to...

install dtaidistance -> Exception: The compiled dtaidistance C library is not available

I try to run dtaidistance but when running the following code according example : from dtaidistance import dtw import numpy as np timeseries = np.array([ [0., 0, 1, 2, 1, 0, 1, 0, 0], ...

What is the meaning of `~` in python grammar

I was going through the python grammer specification and find the following statement, for_stmt: | 'for' star_targets 'in' ~ star_expressions ':' [TYPE_COMMENT] block [else_block] What does...

Calling API in a docker-compose React container to django container using service name

I have a docker compose that containss a react app and other django container. They are in the same network so when I try to make curl request from the react container to one of the django...

Query one more existing MSSQL DB from Linux

I have deployed django application running on Linux (Ubuntu) in VirtualBox. The settings file database section looks like this. DATABASES = { 'default': { 'ENGINE':...

cannot import name '_registerMatType' from 'cv2.cv2'

I got below error message when I run model_main_tf2.py on Object Detection API. " Traceback (most recent call last): File "/content/models/research/object_detection/model_main_tf2.py", line 32,...

cannot import name '_registerMatType' from 'cv2.cv2' (/usr/local/lib/python3.7/dist-packages/cv2/cv2.cpython-37m-x86_64-linux-gnu.so)

I got below error message when I run some codes according to Google Colab:'cannot import name '_registerMatType' from 'cv2.cv2'...