RVC 3rd Edition - rot2 - import?

[xemjeff]

The book introduces python on page 13. It shows a basic command to create a 2d rotational matrix.
Again on page 34.

But nowhere do I see the required import statement. It's not clear where rot2() comes from. I don't find it in roboticstoolbox, or in spatialmath or numpy. I'm missing something obvious, but I don't see the obvious in the book either.

Would someone let me know what to import for rot2()?

Python 3.9.6 (default, Oct 18 2022, 12:41:40) 
[Clang 14.0.0 (clang-1400.0.29.202)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> R = rot2(0.3)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'rot2' is not defined
>>> from roboticstoolbox import *
>>> R = rot2(0.3)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'rot2' is not defined
>>> from spatialmath import *
>>> R = rot2(0.3)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'rot2' is not defined
>>> 

I found it, after snooping around:

>>> from spatialmath.base.transforms2d import *
>>> rot2(0.3)
array([[ 0.95533649, -0.29552021],
       [ 0.29552021,  0.95533649]])
>>> 

Some of this information is in the book on page 79. It comes well after the introduction of the functions.
There is also a python notebook page that has more python preamble:

https://github.com/petercorke/RVC3-python/blob/main/notebooks/chap2.ipynb

[petercorke]

Hi @xemjeff, thank you for your question, and I'm sorry for the long delay: various life events got in the way, and since May I've been doing major work across the Robotics Toolbox, Swift and SpatialGeometry.

rot2 is in spatialmath.base. The rvctool command (installed with the rvc3python package), which is the book's recommended way to run the examples, imports everything from spatialmath.base for you, and that is why the book shows no import. In a plain Python session add from spatialmath.base import * (or just from spatialmath.base import rot2).

I'm closing this as answered; if something still doesn't work, please post an Issue with a short example.