python类abs()的实例源码

def parse_file(self, filename):
        """
        Parses input file into FollowJointTrajectoryGoal format

        @param filename: input filename
        """
        #open recorded file
        with open(filename, 'r') as f:
            lines = f.readlines()
        #read joint names specified in file
        joint_names = lines[0].rstrip().split(',')
        #parse joint names for right limb
        for name in joint_names:
            if self.limb == name[:-3]:
                self.goal.trajectory.joint_names.append(name)

        def find_start_offset(pos):
            #create empty lists
            cur = []
            cmd = []
            dflt_vel = []
            vel_param = self._param_ns + "%s_default_velocity"
            #for all joints find our current and first commanded position
            #reading default velocities from the parameter server if specified
            for name in joint_names:
                if self.limb == name[:-3]:
                    cmd.append(pos[name])
                    cur.append(self.arm.joint_angle(name))
                    prm = rospy.get_param(vel_param % name, 0.25)
                    dflt_vel.append(prm)
            diffs = map(operator.sub, cmd, cur)
            diffs = map(operator.abs, diffs)
            #determine the largest time offset necessary across all joints
            offset = max(map(operator.div, diffs, dflt_vel))
            return offset

        for idx, values in enumerate(lines[1:]):
            #clean each line of file
            cmd, values = self._clean_line(values, joint_names)
            #find allowable time offset for move to start position
            if idx == 0:
                # Set the initial position to be the current pose.
                # This ensures we move slowly to the starting point of the
                # trajectory from the current pose - The user may have moved
                # arm since recording
                cur_cmd = [self.arm.joint_angle(jnt) for jnt in self.goal.trajectory.joint_names]
                self._add_point(cur_cmd, self.limb, 0.0)
                start_offset = find_start_offset(cmd)
                # Gripper playback won't start until the starting movement's
                # duration has passed, and the actual trajectory playback begins
                self._slow_move_offset = start_offset
                self._trajectory_start_offset = rospy.Duration(start_offset + values[0])
            #add a point for this set of commands with recorded time
            cur_cmd = [cmd[jnt] for jnt in self.goal.trajectory.joint_names]
            self._add_point(cur_cmd, self.limb, values[0] + start_offset)
            if self.gripper:
                cur_cmd = [cmd[self.gripper_name]]
                self._add_point(cur_cmd, self.gripper_name, values[0] + start_offset)