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Publishing arrays with rqt_publisher in ROS2

asked 2021-01-26 19:11:18 -0500

ryan.delgizzi gravatar image

updated 2021-01-26 19:11:38 -0500

I am having trouble publishing messages with sequences in them, such as example_interfaces/UInt8MultiArray. By default, the expression is populated with array('B'). When I try to populate with data, such as array('B', [1]) I get errors in the terminal.

[ERROR] [1611709217.176271581] [get_message_class]: Malformed message_type: sequence<double> Python eval failed for expression "array('d',[1])" with an exception "name 'array' is not defined" Publisher._evaluate_expression(): failed to evaluate expression: "array('d',[1])" as Python type "None" Traceback (most recent call last): File "/opt/ros/foxy/lib/python3.8/site-packages/rqt_publisher/publisher.py", line 157, in change_publisher new_text = handler(self._publishers[publisher_id], topic_name, new_value) File "/opt/ros/foxy/lib/python3.8/site-packages/rqt_publisher/publisher.py", line 258, in _change_publisher_expression expression, error_prefix, slot_type.__name__) AttributeError: 'NoneType' object has no attribute '__name__'

Can someone provide an example of proper usage for the expression field?

Thanks!

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answered 2021-02-09 07:58:36 -0500

GeorgeG gravatar image

Did anyone find a way for this?

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Basically it similar to this post and answer. You have to populate data field of the message (of the correct type).

ljaniec gravatar image ljaniec  ( 2021-12-02 18:23:47 -0500 )edit

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Asked: 2021-01-26 19:11:18 -0500

Seen: 300 times

Last updated: Feb 09 '21