1、rosparam list （在定位到文件夹后demo07_ws,查看文件夹(参数服务器)中包含的参数列表）
2、rosparam get /type 用于查看 参数名所带的参数，（其实这里和Java的键值对差不多）
3、修改键值就是重新调用ros::setParam("键名"，“键值”);
4、更新完毕代码后，重新编译，并重新roscore，和rosrun plumbing_param_server demo01_param_set（重新运行文件）更新参数服务器的键值对
5、double radius = nh.param("radius",-0.0);这里的第二个键值的类型，一定要和定义的double一样，不要函数的返回值都将会是0.00000000；第二个参数的意思是：当没有查询到这个键的时候，会返回第二个参数
6、
#include "ros/ros.h"
int main(int argc, char *argv[])
{
setlocale(LC_ALL,"");
ros::init(argc,argv,"get_param");
//NodeHandle--------------------------------------------------------
//param--------------------------------------------------------
ROS_INFO("++++++++++++++++++++++++++++++++++++++++");
int res3 = ros::param::param("param_int",20); //存在
int res4 = ros::param::param("param_int2",20); // 不存在返回默认
ROS_INFO("param获取结果:%d,%d",res3,res4);
// getParam 函数
int param_int_value;
double param_double_value;
bool param_bool_value;
std::string param_string_value;
std::vector param_stus;
std::map param_friends;
ros::param::get("param_int",param_int_value);
ros::param::get("param_double",param_double_value);
ros::param::get("param_bool",param_bool_value);
ros::param::get("param_string",param_string_value);
ros::param::get("param_vector",param_stus);
ros::param::get("param_map",param_friends);
ROS_INFO("getParam获取的结果:%d,%.2f,%s,%d",
param_int_value,
param_double_value,
param_string_value.c_str(),
param_bool_value
);
for (auto &&stu : param_stus)
{
ROS_INFO("stus 元素:%s",stu.c_str());
}
for (auto &&f : param_friends)
{
ROS_INFO("map 元素:%s = %s",f.first.c_str(), f.second.c_str());
}
// getParamCached()
ros::param::getCached("param_int",param_int_value);
ROS_INFO("通过缓存获取数据:%d",param_int_value);
//getParamNames()
std::vector param_names2;
ros::param::getParamNames(param_names2);
for (auto &&name : param_names2)
{
ROS_INFO("名称解析name = %s",name.c_str());
}
ROS_INFO("----------------------------");
ROS_INFO("存在 param_int 吗? %d",ros::param::has("param_int"));
ROS_INFO("存在 param_intttt 吗? %d",ros::param::has("param_intttt"));
std::string key;
ros::param::search("param_int",key);
ROS_INFO("搜索键:%s",key.c_str());
return 0;
}
7、python实现
#! /usr/bin/env python
"""
参数服务器操作之新增与修改(二者API一样)_Python实现:
"""
import rospy
if __name__ == "__main__":
rospy.init_node("set_update_paramter_p")
# 设置各种类型参数
rospy.set_param("p_int",10)
rospy.set_param("p_double",3.14)
rospy.set_param("p_bool",True)
rospy.set_param("p_string","hello python")
rospy.set_param("p_list",["hello","haha","xixi"])
rospy.set_param("p_dict",{"name":"hulu","age":8})
# 修改
rospy.set_param("p_int",100)
#! /usr/bin/env python
"""
参数服务器操作之查询_Python实现:
get_param(键,默认值)
当键存在时，返回对应的值，如果不存在返回默认值
get_param_cached
get_param_names
has_param
search_param
"""
import rospy
if __name__ == "__main__":
rospy.init_node("get_param_p")
#获取参数
int_value = rospy.get_param("p_int",10000)
double_value = rospy.get_param("p_double")
bool_value = rospy.get_param("p_bool")
string_value = rospy.get_param("p_string")
p_list = rospy.get_param("p_list")
p_dict = rospy.get_param("p_dict")
rospy.loginfo("获取的数据:%d,%.2f,%d,%s",
int_value,
double_value,
bool_value,
string_value)
for ele in p_list:
rospy.loginfo("ele = %s", ele)
rospy.loginfo("name = %s, age = %d",p_dict["name"],p_dict["age"])
# get_param_cached
int_cached = rospy.get_param_cached("p_int")
rospy.loginfo("缓存数据:%d",int_cached)
# get_param_names
names = rospy.get_param_names()
for name in names:
rospy.loginfo("name = %s",name)
rospy.loginfo("-"*80)
# has_param
flag = rospy.has_param("p_int")
rospy.loginfo("包含p_int吗？%d",flag)
# search_param
key = rospy.search_param("p_int")
rospy.loginfo("搜索的键 = %s",key)
#! /usr/bin/env python
"""
参数服务器操作之删除_Python实现:
rospy.delete_param("键")
键存在时，可以删除成功，键不存在时，会抛出异常
"""
import rospy
if __name__ == "__main__":
rospy.init_node("delete_param_p")
try:
rospy.delete_param("p_int")
except Exception as e:
rospy.loginfo("删除失败")
#这里是一个抛出异常的操作，程序很大时让整个程序不至于卡住
8、python快速多行注释ctrl+shift+A
