Python program to calculate harmonic series

Question

Does anyone know how to write a program in Python that will calculate the addition of the harmonic series. i.e. 1 + 1/2 +1/3 +1/4...

Answer 1

@recursive's solution is correct for a floating point approximation. If you prefer, you can get the exact answer in Python 3.0 using the fractions module:

>>> from fractions import Fraction
>>> def calc_harmonic(n):
...   return sum(Fraction(1, d) for d in range(1, n + 1))
...
>>> calc_harmonic(20) # sum of the first 20 terms
Fraction(55835135, 15519504)

Note that the number of digits grows quickly so this will require a lot of memory for large n. You could also use a generator to look at the series of partial sums if you wanted to get really fancy.