Python class has no attribute when calling function

Question

I have this kind of problem attributeError: module 'ResponseLayer' has no attribute 'RS'. I am a beginner just started learning python from scratch. What do i need to understand here? Am i wrong coding this?

class ResponseLayer:
 def RS(self,_width, _height, _step, _filter):
 self.width = _width
 self.height = _height
 self.step = _step
 self.filterr = _filter
class FastHessian:
 import ResponseLayer
 def buildResponseMap():
 responseMap = []
 w = int(img.Width / init)
 h = int(img.Height / init)
 s = int(init)
 if (octaves >=1):
 responseMap.append(RS(w, h, s, 9))
 responseMap.append(RS(w, h, s, 15))
 responseMap.append(RS(w, h, s, 21))
 responseMap.append(RS(w, h, s, 27))

• glibdud: Could you provide the full traceback? I don't see what line of the provided code would produce that error. It might also help to describe what you're trying to accomplish with this code. Some of it looks strange, but I can't tell what you should be doing instead if I don't know what you're trying to do.
• TemporalWolf: Welcome to Stack Overflow! Your code does not run for several reasons (img and octaves are not defined, for example). Please edit your question to include enough code that we can run it. See minimal reproducible example.
• chepner: import ReponseLayer implies you have a file named ResponseLayer.py somewhere, and the module is distinct from the any class by the same name that might defined in the file. Further, RS is a method, not a class, so it's not clear what code is generating the AttributeError or why you aren't getting a NameError on the use of RS you show.
• chepner: You should work through the tutorial, though; your code looks like someone trying to write Java in Python, rather than real Python code.

Answer 1

Ianny,

If all the code you've shown live in the same file, then you don't have to import ResponseLayer.

I believe you're adding unique instances of ResponseLayer to a response map.

If I am correct, then you should change that RS method on ResponseLayer class to an instance creation method (init in Python).

So that you just write ResponseLayer(20, 30, 2, 4) to create an example response layer object.

This is what I mean:

class ResponseLayer:
 def __init__(self, width, height, step, _filter):
 self.width = width
 self.height = height
 self.step = step
 self._filter = _filter
class FastHessian:
 def buildResponseMap():
 responseMap = []
 w = int(img.Width / init)
 h = int(img.Height / init)
 s = int(init)
 if (octaves>= 1):
 responseMap.append(ResponseLayer(w, h, s, 9))
 responseMap.append(ResponseLayer(w, h, s, 15))
 responseMap.append(ResponseLayer(w, h, s, 21))
 responseMap.append(ResponseLayer(w, h, s, 27))

I understand you are a Python beginner.

Welcome to the world of Python.

I love helping beginners level up in my areas of strength. Like @chepner mentioned, your code looks too Java for Python. I would love to help you rewrite it to be more Pythonic. Feel free to chat me up here on StackOverflow.