param_talker.py
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00001 #!/usr/bin/env python
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00034 # Revision $Id: listener.py 5263 2009-07-17 23:30:38Z sfkwc $
00035 
00036 ## Simple talker demo that listens to std_msgs/Strings published 
00037 ## to the 'chatter' topic
00038 
00039 import rospy
00040 from std_msgs.msg import String
00041 
00042 def param_talker():
00043     rospy.init_node('param_talker')
00044 
00045     # Fetch values from the Parameter Server. In this example, we fetch
00046     # parameters from three different namespaces:
00047     #
00048     # 1) global (/global_example)
00049     # 2) parent (/foo/utterance)
00050     # 3) private (/foo/param_talker/topic_name)
00051 
00052     # fetch a /global parameter
00053     global_example = rospy.get_param("/global_example")
00054     rospy.loginfo("%s is %s", rospy.resolve_name('/global_example'), global_example)
00055     
00056     # fetch the utterance parameter from our parent namespace
00057     utterance = rospy.get_param('utterance')
00058     rospy.loginfo("%s is %s", rospy.resolve_name('utterance'), utterance)
00059     
00060     # fetch topic_name from the ~private namespace
00061     topic_name = rospy.get_param('~topic_name')
00062     rospy.loginfo("%s is %s", rospy.resolve_name('~topic_name'), topic_name)
00063 
00064     # fetch a parameter, using 'default_value' if it doesn't exist
00065     default_param = rospy.get_param('default_param', 'default_value')
00066     rospy.loginfo('%s is %s', rospy.resolve_name('default_param'), default_param)
00067     
00068     # fetch a group (dictionary) of parameters
00069     gains = rospy.get_param('gains')
00070     p, i, d = gains['P'], gains['I'], gains['D']
00071     rospy.loginfo("gains are %s, %s, %s", p, i, d)    
00072 
00073     # set some parameters
00074     rospy.loginfo('setting parameters...')
00075     rospy.set_param('list_of_floats', [1., 2., 3., 4.])
00076     rospy.set_param('bool_True', True)
00077     rospy.set_param('~private_bar', 1+2)
00078     rospy.set_param('to_delete', 'baz')
00079     rospy.loginfo('...parameters have been set')
00080 
00081     # delete a parameter
00082     if rospy.has_param('to_delete'):
00083         rospy.delete_param('to_delete')
00084         rospy.loginfo("deleted %s parameter"%rospy.resolve_name('to_delete'))
00085     else:
00086         rospy.loginfo('parameter %s was already deleted'%rospy.resolve_name('to_delete'))
00087 
00088     # search for a parameter
00089     param_name = rospy.search_param('global_example')
00090     rospy.loginfo('found global_example parameter under key: %s'%param_name)
00091     
00092     # publish the value of utterance repeatedly
00093     pub = rospy.Publisher(topic_name, String)
00094     while not rospy.is_shutdown():
00095         pub.publish(utterance)
00096         rospy.loginfo(utterance)
00097         rospy.sleep(1)
00098         
00099 if __name__ == '__main__':
00100     try:
00101         param_talker()
00102     except rospy.ROSInterruptException: pass
00103     


rospy_tutorials
Author(s): Ken Conley
autogenerated on Fri Aug 28 2015 12:38:27