ROS1を使ってみる　その２（PythonのコードでPublishとSubscribe）

mkdir -p ~/book_ws/src
cd book_ws/src
catkin_init_workspace
cd ~/book_ws
catkin_make

source ~/book_ws/devel/setup.bash

cd ~/book_ws/src
catkin_create_pkg ros_start rospy roscpp std_msgs
cd ~/book_ws
catkin_make
source ~/book_ws/devel/setup.bash

cd ~/book_ws/src/ros_start/
mkdir scripts
cd scripts

#!/usr/bin/python3.8
import rospy
from std_msgs.msg import String

rospy.init_node('talker')
pub = rospy.Publisher('chatter', String, queue_size=10)
rate = rospy.Rate(10)
while not rospy.is_shutdown():
        hello_str = String()
        hello_str.data = "hello world %s" % rospy.get_time()
        pub.publish(hello_str)
        rate.sleep()

#!/usr/bin/python3.8
import rospy
from std_msgs.msg import String
def callback(message):
        rospy.loginfo("I heard %s", message.data)

rospy.init_node('listener')
sub = rospy.Subscriber('chatter', String, callback)
rospy.spin()

sudo chmod 755 talker.py listener.py

roscore

cd book_ws
source devel/setup.bash
roscd ros_start/scripts/
./talker.py

cd book_ws
source devel/setup.bash
roscd ros_start/scripts/
./listener.py

<launch>
        <node pkg="ros_start" name="talker" type="talker.py"/>
        <node pkg="ros_start" name="listener" type="listener.py"/>
</launch>

roslaunch ros_start chat.launch

roslaunch ros_start chat.launch --screen

<launch>
        <node pkg="ros_start" name="talker" type="talker.py"/>
        <node pkg="ros_start" name="listener" type="listener.py" output="screen"/>
</launch>

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--extra-index-url https://rospypi.github.io/simple rospy-all