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Is there any way to recover the number of messages of a given topic from a .bag file using the C++ API?
I know the Python API does, which is used in rosbag info <bag> (I think, by means of the _get_yaml_info Bag class method), but I'd like to know whether we have the same feature in the C++ API or not?
Thanks!
Did you try the rosbag::View::size method? As I understand it, it should return the number of messages. Maybe std::distance(view.begin(), view.end()) could also work, but not sure about that.
I mean to obtain the number of messages without reading them, like rosbag info does (as I mention in my question). Currently, I read all messages using C++ API, and I convert them to some ASCII files I need, but only at the end I know the number of messages, and I need it at the very beginning.
@Enrique Hi. I met almost the same question or need to get the number of messages in a rosbag. I used the function view.size() but it showed the size_cache (uint32) and it was 68435, not the value of the messages number. How could I make it works? Thank you
Asked: 2012-02-28 22:10:21 -0600
Seen: 1,789 times
Last updated: Feb 29 '12
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