Why is the float * int multiplication faster than int * float in CPython? Question: Basically, the expression 0.4 * a is consistently, and surprisingly, significantly faster than a * 0.4. a being an integer. And I have no idea why. I speculated that it is a case of a LOAD_CONST LOAD_FAST bytecode pair being …
How to convert python code into a simple c haeder? Question: I’m Working on a program that takes in text from the user and then implements functionalities in the backend, kind of like an interpreter, I have the parser working amazingly in python but some of the backend capabilities I feel would do great on …
XOR encryption with a PyObject Question: I’m having trouble encrypting bytes from a PyObject using XOR. For now I only managed to print the bytes as an encoded string (with PyUnicode_AsEncodedString): Here’s what I tried (taken from this SO answer) PyObject* repr = PyObject_Repr(wf.str); // wf.str is a PyObject * PyObject* str = PyUnicode_AsEncodedString(repr, "utf-8", …
compile official doc "Embedding Python in Another Application" example failed Question: I am trying to compile and run the example from https://docs.python.org/3/extending/embedding.html#very-high-level-embedding , but failed. My environment is Ubuntu 20.04.2 LTS, with system shipped python3.8(statically built), libpython3-dev and libpython3.8-dev packages installed. What I’ve tried: main.c : #define PY_SSIZE_T_CLEAN #include <Python.h> int main(int argc, char *argv[]) …
MacOS M1 system is detected as ARM by Python package even though I'm using Rosetta Question: I’m on a Macbook with M1 (Apple ARM architecture) and I’ve tried running the following Python code using the layoutparser library, which indirectly uses pycocotools: import layoutparser as lp lp.Detectron2LayoutModel() And I’ve received the error: […] ImportError: dlopen([…]/.venv/lib/python3.9/site-packages/pycocotools/_mask.cpython-39-darwin.so, 0x0002): …
Why don't Python sets preserve insertion order? Question: I was surprised to discover recently that while dicts are guaranteed to preserve insertion order in Python 3.7+, sets are not: >>> d = {‘a’: 1, ‘b’: 2, ‘c’: 3} >>> d {‘a’: 1, ‘b’: 2, ‘c’: 3} >>> d[‘d’] = 4 >>> d {‘a’: 1, ‘b’: …
What causes [*a] to overallocate? Question: Apparently list(a) doesn’t overallocate, [x for x in a] overallocates at some points, and [*a] overallocates all the time? Here are sizes n from 0 to 12 and the resulting sizes in bytes for the three methods: 0 56 56 56 1 64 88 88 2 72 88 96 …
Running Python code in parallel from Rust with rust-cpython Question: I’m trying to speed up a data pipeline using Rust. The pipeline contains bits of Python code that I don’t want to modify, so I’m trying to run them as-is from Rust using rust-cpython and multiple threads. However, the performance is not what I expected, …
Possible to get "value of address" in python? Question: In the following, I can see that when adding an integer in python, it adds the integer, assigns that resultant value to a new memory address and then sets the variable to point to that memory address: >>> a=100 >>> id(a) 4304852448 >>> a+=5 >>> id(a) …
embed python environment in c++ application Question: Using the c-python api I try to embed python 3.6 into a c++ application. However instead of using the system install i’d like to use a virtual environment. I didn’t find any documentation on the way to do that. Some related documentation mention py_SetProgramName or py_SetPythonHome Also when …
