How can I convert numbers with decimals to fractions in Python?
I would like to print numeric values with decimals in their fraction Form:
0.5 a 1/2 0.75 a 3/4 4.5 a 9/2
Is there any Native library to perform the conversion? How is such a conversion performed?
3 answers
You can use the Class Fraction of the module fractions:
>>> from fractions import Fraction
>>> a = Fraction('0.5')
>>> b = Fraction('0.75')
>>> c = Fraction('4.5')
>>> print(a)
1/2
>>> print(b)
3/4
>>> print(c)
9/2
If you have the numbers saved as real, then you can do the explicit conversion using str and then pass that the Class Fraction.
You can make a recursive function that delivers values for the numerator and denominator of the fraction, regardless of whether it is simplified or not. Then you simplify or factor with Euclid's algorithm.
I leave you the code for the algorithm.
def mcd(a,b):
assert type(a) == int and type(b) == int and a>0 and b>0
if a%b != 0:
return mcd(b,a%b)
else:
return b
Then you do something like numerador=numerador/mcd(numerador,denominador) and denominador=denominador/mcd(numerador,denominador) and print it as string:
print(str(numerador)+'/'+str(denominador)).
Using the Class Fraction of the module fractions does not return the value of the fraction when it has infinite decimal numbers, therefore it is necessary to add .limit_denominator() after using the class.
from fractions import Fraction
a = 2/9
b=Fraction(str(a))
print('Valor de b: ',b)
c=Fraction(str(a)).limit_denominator()
print('Valor de c: ',c)
And as a result:
Valor de b: 1111111111111111/5000000000000000
Valor de c: 2/9