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ImportError: dynamic module does not define module export function (PyInit__tf2)

asked 2021-01-19 00:04:56 -0600

siddharthcb gravatar image

updated 2021-01-19 00:06:16 -0600

hi, i am trying to run a package built from source on ros melodic. when i run the command i end up with this error:

from tf import TransformListener
  File "/opt/ros/melodic/lib/python2.7/dist-packages/tf/", line 30, in <module>
    from tf2_ros import TransformException as Exception, ConnectivityException, LookupException, ExtrapolationException
  File "/opt/ros/melodic/lib/python2.7/dist-packages/tf2_ros/", line 38, in <module>
    from tf2_py import *
  File "/opt/ros/melodic/lib/python2.7/dist-packages/tf2_py/", line 38, in <module>
    from ._tf2 import *

from this i understood that it is conflicting with the python path but this solution did not work for me and i get the same error. is there any other way to setup catkin_ws with python3?

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No solution, rather a comment: Using python3 in ROS (pre-noetic) is hard! You'd have to compile everything from source to make this work properly and stumble upon hundreds of problem over and over again. A quick search for this will turn up many, many questions on that, that, in the end all (should) say:

If you need to use python3, use ROS noetic!

(personal opinion, but I'm 100% positive, that this will make your life a lot easier...)

mgruhler gravatar image mgruhler  ( 2021-01-19 02:43:27 -0600 )edit

and stumble upon hundreds of problem over and over again

well, hundreds, that's a bit much perhaps, but I do agree with the advice about using Noetic if you have Python 3 requirements.

gvdhoorn gravatar image gvdhoorn  ( 2021-01-19 04:39:30 -0600 )edit

well, hundreds, that's a bit much perhaps

well, yeah, I like to exaggerate ;-)

mgruhler gravatar image mgruhler  ( 2021-01-19 04:44:05 -0600 )edit

thanks guys! i tried for few days and went on solving errors one by one but ended up crashing everything the entire image and had to flash a new image from scratch :/

i will keep in mind what @mgruhler suggested from next time.

siddharthcb gravatar image siddharthcb  ( 2021-01-28 12:22:04 -0600 )edit

could you close this issue with the appropriate resolution, if you are okay with that? thank you.

mgruhler gravatar image mgruhler  ( 2021-01-29 00:57:30 -0600 )edit

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answered 2021-01-31 05:41:12 -0600

siddharthcb gravatar image

updated 2021-10-12 01:00:59 -0600

As @mgruhler and @gvdhoom pointed out, yes, prenoetic with python3 will land you in so many problems. its better to switch to noetic if you need to work on python3.

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Asked: 2021-01-19 00:04:56 -0600

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Last updated: Oct 12 '21