关于列表赋值的效率问题

import time


def main():
        t1=time.time()
        count1={}
        count2={}
        for i in range(1000000):
                count1[i]=[]
                count1[i].append(i)
        t2=time.time()
        count2=count1
        t3=time.time()
        print(t2-t1,t3-t2)
        #0.5702214241027832 1.9073486328125e-06
main()