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How to get length of array if poses from nav_msgs/Path.msg

asked 2022-01-23 12:53:27 -0500

distro gravatar image

Does anyone know how to use the message type nav_msgs/Path.msg. according to the wiki it is an array of poses that are used to plan a path but it I'm unable to get the msg in array form. I need to get the length of the array for my purposes which is why I'm asking. How do I go about that? right now I just have this:

import rospy
from nav_msgs.msg import Path
from rospy.numpy_msg import numpy_msg
import numpy as np

def callback(msg):
    print("list: ", msg)

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2 Answers

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answered 2022-01-24 13:45:18 -0500

distro gravatar image

updated 2022-01-24 13:46:42 -0500

Thanks guys! I typed pose instead of poses, that messed me up. Its fixed now, its len(msg.poses)

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answered 2022-01-23 14:05:57 -0500

ljaniec gravatar image

updated 2022-01-23 16:49:20 -0500

Shouldn't it be rather print("list: ", in your callback? Check ROS documentation there for correct form of ROS1 subscriber. The array poses can be acquired as the field of

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You can access the whole Path with and the pose list with To get the length, you would need to use print("list: ", len(

miura gravatar image miura  ( 2022-01-23 16:44:16 -0500 )edit

@ljaniec when I used it gave an error about Path not having attribute data or something like that.

distro gravatar image distro  ( 2022-01-24 12:06:29 -0500 )edit

@ljaniec I figured it out thanks!

distro gravatar image distro  ( 2022-01-24 13:48:00 -0500 )edit

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Asked: 2022-01-23 12:53:27 -0500

Seen: 444 times

Last updated: Jan 24 '22