ROS parameter server

First create a function package in the workspace

catkin_create_pkg test_param std_msgs roscpp rospy

Create a... Under the feature pack param Folder

stay param Create one under the folder param.yaml file
The contents are as follows ：

string: dsad3421
num1: 564.65
num2: 87896
sub_param_set:
  string: cvvx
  num: 423
  sub_sub_param_set:
    string: gfdg
    num: 767

Then load the parameters ：
First run

roscore

And then param Run under folder directory

rosparam load param.yaml
rosparam list

give the result as follows ：

It can be used rosparam get and rosparam set To get and set parameter values

The function of the package is src Create under directory test_param.cpp

Fill in the following ：

#include <string>
#include <ros/ros.h>
int main(int argc, char **argv)
{
     int aaa;
    // ROS Node initialization 
    ros::init(argc, argv, "parameter_config");
    //  Create node handle 
    ros::NodeHandle node;
    ros::param::get("/sub_param/num", aaa);
    ROS_INFO("aaa=%d\n", aaa);
    return 0;
}

The function of the package is CMakeLists.txt Add ：

add_executable(test_param src/test_param.cpp)
target_link_libraries(test_param ${catkin_LIBRARIES})

then catkin_make Run... After compilation

rosrun test_param test_param

give the result as follows , When running this node , Must use rosparam load After loading the parameter file ,ROS Inner talent get To the value of the parameter , I used it here before rosparam set Set parameters /sub_param/num The value of is 456, So here get The value of is 456, without set, Then this value is the value in the parameter file