rospy subscribing to topic, how can i save a variable?

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Hi

I'm fairly new to programming in python and ROS, but my problem is as follows: I am using a robot gripper, and for control purposes i need to read the status of the gripper and save it to a variable, so I can use if in control sequences. I am getting the status of the gripper by subscribing to a topic.

import roslib; roslib.load_manifest('robotiq_s_model_control')
import rospy
from robotiq_s_model_control.msg import _SModel_robot_input  as inputMsg
from robotiq_s_model_control.msg import _SModel_robot_output  as outputMsg

def Callback(data):
    myvar = data

rospy.init_node('rq3_proxy')

while not rospy.is_shutdown():
    rospy.Subscriber("SModelRobotInput", inputMsg.SModel_robot_input, Callback)
    rospy.sleep(1)

    print "myvar is: " + myvar

    if myvar == 1:
         #do something"
    elif myvar == 0:
         #do something else
    else :
         #error

So my question is: how can I make use of the myvar variable outside the Callback function?

Thanks in advance for any help you can provide, and if you need additional info, just ask for it.

/Morten