How to read only once a message published in a topic?
I created a ROS node that continuously publishes a geometry_msgs/Pose type message within a topic, the published information comes from a sensor, I would like to know if it is possible to read only a single topic message instead of reading all the messages that are being published to the queue.
The following image shows the information that is published within the topic. How can I get the information from a single message to store it inside a variable?
If I use a subscriber node, the callback() function reads all the information that is being published on the topic and I only want to access a single message.
Asked by LuisEFA1998 on 2022-07-04 20:03:15 UTC
Comments
You can "echo" or print a single message from a particular ROS topic using:
rostopic echo -n COUNTwhere COUNT equals the number of messages you want to print or see.I figured this out using
rostopic echo -h.Cheers
Asked by electrophod on 2022-07-05 00:42:16 UTC
I've closed this as a duplicate, as it is a duplicate of at least #q270298, #q222029, #q292582, #q62176 and a couple more.
You might have done so already, but for future readers: please search before posting. And use Google: append
site:answers.ros.orgto your search query. For me,subscribe only once site:answers.ros.orgreturns many results, including the Q&As I've linked.Asked by gvdhoorn on 2022-07-05 01:36:01 UTC
Additionally, @LuisEFA1998:
please do not post screenshots of terminals. This goes against the support guidelines and is also unnecessary. It's all text, so copy-paste the text into your question, then format it using the Preformatted Text button (the one with
101010on it).Asked by gvdhoorn on 2022-07-05 01:37:35 UTC