我想让这个程序做他们的输入的东西的总结。我的代码迄今如何使raw_input不是字符串在python
def summation():
start = int(raw_input("Start value of n?: "))
end = int(raw_input("End value of n?: "))
eqn = lambda n: raw_input("Equation?: ")
sum = 0
for i in range(start , end + 1):
sum += eqn(i)
return sum
print summation() # start will be 1, end will be 5 , equation will be n + 1. Should print 20
,我感到我不能添加一个整数和一个串起来,那么,有没有办法让对等式的raw_input的不是字符串错误。像它不是'n + 1',我希望它是n + 1.