Summation of Equation Program

Question

So basically I'm trying to make a program that will do equation for every value of nStart to nEnd. This is my code so far

def summation(nStart , nEnd , eqn): 
    sum = 0
    while nStart - 1 != nEnd:
        sum = sum + eqn
        nStart += 1
    return sum

print summation(1 , 5 ,  n + 1)

I get that n is not defined in the last line. I guess it's because I have n + 1 but how do I solve that? I tried making n = 0 but then that doesn't help because then eqn is just 1 and not an equation.

Answer 1

You could use a lambda function as an argument. For example:

def summation(start, end, eqn):
    sum = 0
    # Note that the *end* value will not be used, since range stops at *end-1*
    for i in range(start, end):
        sum+=eqn(i)
    return sum

print summation(0,10,lambda x: x+1)
print summation(0,10,lambda x: x**2)

Will return:

55
285

Since

Hope this gives you a useful tool to explore and modify if it doesn't do exactly what you are after.