How to increment fraction/denominator in loop?

Question

I'm trying to develop a Python 3 program that will allow the user to choose a denominator and evaluate an equation. For Example:

My code:

d = input ("Select a denominator") 
for i in range(d)
    d += (1/d)
    print(d)

So far I'm only able to ask the user for the input/denominator. I tried putting it in a loop but I am doing something wrong. This is what prints out:

[How to debug small programs](https://ericlippert.com/2014/03/05/how-to-debug-small-programs/) — Pranav Hosangadi, Aug 25 '20 at 18:23
change first line in loop to `d += 1/i` and the range to `range(1,d+1)` — Jab, Aug 25 '20 at 18:23
Your meta-problem is lack of debugging. Insert a simple, tracing `print` at the top of your loop, such as `print(i, d)` and look at the values. Do they match what you did when you worked through the problem by hand? Your code has several problems; test one line -- or even one expression -- at a time. Don't add more until the first part works. — Prune, Aug 25 '20 at 18:24
Does this answer your question? [How can I read inputs as numbers?](https://stackoverflow.com/questions/20449427/how-can-i-read-inputs-as-numbers) — Trenton McKinney, Aug 25 '20 at 18:28

Jasmijn · Answer 1 · 2020-08-25T18:30:03.233

final_denominator = int(input("Select a denominator: "))
total = 0
for i in range(1, final_denominator + 1):
    total += 1 / i
print(total)

You need to convert the inputted string to an integer with int()
Use a different variable for the total and the final denominator.
range(x) goes from 0 to x - 1, to go from 1 to x you need range(1, x + 1).
You need to add 1 / i rather than 1 / final_denominator to the total.

Alternatively, this is a good use for a generator expression:

final_denominator = int(input("Select a denominator: "))
total = sum(1 / i for i in range(1, final_denominator + 1))
print(total)

I forgot to add `int()`, already fixed it. – Jasmijn Aug 25 '20 at 18:30 — Jasmijn, Aug 25 '20 at 18:30

1 Answers1