Feature2D, feature extraction, A problem

I found that the results of feature extraction with opencv, feature2D, detect() are saved as:

[<KeyPoint 0x7f36b5b74e10>, <KeyPoint 0x7f36b5b529f0>, <KeyPoint 0x7f36b47fb030>, < KeyPoint 0x7f35e32f6030>, ...]

What data format is this? < > What is the format? What does KeyPoint stand for? What does 0x7f36b47fb030 stand for? Is there a corresponding implementation of the code for reference?

Thank you very much for your advice!

you got a list of KeyPoint objects

it’s the in-memory address of a resp. kp.

opencv is a c++ library, there is no python code for this.
however, have a look at the src code

just to clarify - this only detects keypoints. computing feaures for those is done in a diferent step (compute())

that is how objects represent themselves in Python if their full state can’t or shouldn’t be in the “repr”. learn about python:

https://docs.python.org/3/library/functions.html#repr