traci.vehicle.getContextSubscriptionResults(egoID)

[shuowang572875852]

Hello,
I want to add traci.vehicle.getContextSubscriptionResults(egoID) to get the surround vehicle ID, but the output “ans” is 1*1Map ,the follow is my code:

clear
close all
clc

import traci.constants
scenarioPath=['F:\software\SUMO配置文件\bin\quickstart\quickstart.sumocfg'];
system(['sumo-gui -c ' '"' scenarioPath '"' ' --remote-port 8813 --start&']);
traci.init

SIM_STEPS = [1 900];
beginTime = SIM_STEPS(1);
duration = SIM_STEPS(2);
endTime = SIM_STEPS(1) + SIM_STEPS(2) - 1;

for i = 1:duration
traci.simulation.step();
IDList{i,1} = traci.vehicle.getIDList();
for j=1:length(IDList{i,1})
accel{i,1}(j)=traci.vehicle.getAcceleration(char(IDList{i,1}(1:end,j)));
laneID{i,1}=traci.vehicle.getLaneID(char(IDList{i,1}(1:end,j)));
traci.vehicle.subscribeContext(char(IDList{i,1}(1:end,j)), traci.constants.CMD_GET_VEHICLE_VARIABLE,150,{traci.constants.VAR_POSITION, traci.constants.VAR_SPEED});
traci.vehicle.addSubscriptionFilterLeadFollow('1');
contextSubscriptionResults=traci.vehicle.getContextSubscriptionResults(char(IDList{i,1}(1:end,j)));
end
end
traci.close()

looking forward to your reply.