AttributeError: NumberLine object has no attribute 'default_numbers_to_display' when calling get_number_mobjects()

[kevinnadar22]

Description of bug / unexpected behavior

When attempting to use get_number_mobjects() on a NumberLine object, I encountered the following error:

AttributeError: NumberLine object has no attribute 'default_numbers_to_display'

It seems like the method get_number_mobjects() internally calls self.default_numbers_to_display(), but this method is either missing or no longer available in the current implementation of NumberLine.

Expected behavior

Calling get_number_mobjects() with no arguments should use default numbers (e.g., from x_range) to generate label mobjects.

How to reproduce the issue

1. Create a NumberLine object.
2. Call get_number_mobjects() without passing any explicit numbers.
3. Run the scene.

Code for reproducing the problem

from manim import *

class IntroductionToComplexNumbers(Scene):
    def construct(self):
        # Create real number line
        real_number_line = NumberLine(
            x_range=[-5, 5, 1],
            length=10,
            include_tip=False,
        )
        real_number_line_labels = real_number_line.get_number_mobjects()
        self.add(real_number_line, *real_number_line_labels)

Logs

Terminal output

Logs

System specifications

System Details

Environment

* **OS:** Windows 11
* **Manim version:** (e.g., v0.19.0) 
* **Python version:** (e.g., 3.10)
* **Installation:** pip

[irvanalhaq9]

It seems that the method .default_numbers_to_display() has been removed from Manim Community, but the code wasn't updated accordingly.
If your goal is to display numbers along the number line, you can do either of the following:

1. Use .add_numbers() after creating NumberLine object:

   class IntroductionToComplexNumbers(Scene):
       def construct(self):
           real_number_line = NumberLine(
               x_range=[-5, 5, 1],
               length=10,
               include_tip=False,
           )
           real_number_line.add_numbers()
           self.add(real_number_line)

2. Or, set include_numbers=True directly in the constructor:

   class IntroductionToComplexNumbers(Scene):
       def construct(self):
           real_number_line = NumberLine(
               x_range=[-5, 5, 1],
               length=10,
               include_tip=False,
               include_numbers=True,
           )
           self.add(real_number_line)

For more details, see the documentation:
👉 NumberLine — Manim Documentation

[irvanalhaq9]

Hi @kevinnadar22

I think this issue still needs to be addressed.

When users call .get_number_mobjects() or .get_labels() on a NumberLine object, it will still raise an AttributeError because .default_numbers_to_display() is being accessed but doesn't exist.