python计算收益率的效率分析-sympy包-计算呈指数递增，大量计算不考虑

from sympy import *
import time
import datetime
for i in range(1,50):
    print('第'+str(i)+'次计算开始')
    x = Symbol('x')
    startTime=time.strftime('%Y-%m-%d %H:%M:%S',time.localtime())
    print(startTime)
    mystr=''
    for j in range(1,i+1):
        mystr+='+x**'+str(j)
    mystr=mystr[1:]
    xx=solve(eval(mystr)-1.1*i,x)
    endTime=time.strftime('%Y-%m-%d %H:%M:%S',time.localtime())
    print(endTime)
    startTime= datetime.datetime.strptime(startTime,"%Y-%m-%d %H:%M:%S")  
    endTime= datetime.datetime.strptime(endTime,"%Y-%m-%d %H:%M:%S")
    seconds = (endTime- startTime).seconds  
    print('第{}次方方程计算耗费的时间为{}秒'.format(i,seconds))