Converting recurring decimals to fractions in Python

Question

I have the below, where I am converting decimals to fractions. It works, 0.6 becomes 3/5.

However, if I had 0.666666666666. I'd expect it to be 2/3. How can I achieve this?

#set starting parameters
decimal = 0.6
starting_denominator = 100
starting_numerator = int(decimal * 100)

print('starting fraction: '+str(starting_numerator) + '/' + str(starting_denominator))

#find the common factors for the numerator and denominator
i = 1
numerator_factors = []
denominator_factors = []

while i < starting_numerator+1:
    if starting_numerator%i == 0:
        numerator_factors.append(i)
    i = i+1

i = 1
while i < starting_denominator+1:
    if starting_denominator%i == 0:
        denominator_factors.append(i)
    i = i+1   

print('numerator factors: '+ str(numerator_factors))
print('denominator factors: '+ str(denominator_factors))

#Find matching factors and find highest across both
matches = []

for numfactor in numerator_factors:
    for denfactor in denominator_factors:
        if numfactor == denfactor:
            matches.append(numfactor)

end_numerator = starting_numerator/max(matches)
end_denominator = starting_denominator/max(matches)

print('end fraction: '+str(int(end_numerator)) + '/' + str(int(end_denominator)))

Does this answer your question? [How to convert a decimal number into fraction?](https://stackoverflow.com/questions/23344185/how-to-convert-a-decimal-number-into-fraction) — Nathan, Jan 09 '20 at 10:40
@Nathan yes that will answer the question but not completely — Vaibhav Jadhav, Jan 09 '20 at 10:42

score 7 · Accepted Answer · answered Jan 09 '20 at 10:40

7

Here is the solution for your question:

from fractions import Fraction
res = Fraction(0.66666666666).limit_denominator()
print(res)

answered Jan 09 '20 at 10:40

Vaibhav Jadhav

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@kikee1222 Is this what are you looking for? – Vaibhav Jadhav Jan 09 '20 at 11:55

Converting recurring decimals to fractions in Python

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