Python - Execute A String Code For Fractions

I've been working in some type of calculator for fractions using from fractions import * following the next logic: a = Fraction(1,4) b = Fraction(2,5) c = Fraction(3,4) print(a+b*

Solution 1:

I tried this and this is working (my input was in the form a/b + c/d):

from fractions import*

print ("your operation:")

op = input()
#print (op)

elements = op.split()

for el in elements:
    if ('/'in el):
       fraction = el.split('/')
       numerator = fraction[0]
       denominator = fraction[1]

       a = Fraction(int(numerator),int(denominator))

    print (numerator)
    print (denominator)
    print (a)

Solution 2:

You can use ast eval

import ast

defmyfunc():
   localvars = {}
   expr = 'x = 1/4 + 1/2'eval(compile(ast.parse(expr), '<input>', mode="exec"), localvars)
   return localvars['x']

Note, in python 2 it will yield 0 as both 1/4 and 1/2 will result in 0, you need to do 1.0/4 in python 2. python3 will calculate it using double types so it will return 0.75 as you expect , ie python2 version:

import ast

 defmyfunc():
    localvars = {}
    expr = 'x = 1.0/4 + 1.0/2'eval(compile(ast.parse(expr), '<input>', mode="exec"), localvars)
    return localvars['x']

Solution 3:

You can do something like this:

from fractions import *

defreturnElement(element):
    if'/'in element andlen(element) > 1:
        fraction = element.split('/')
        numerator = fraction[0]
        denominator = fraction[1]
        return'Fraction(' + numerator + ',' + denominator + ')'else:
        return element  

classmain():
    for i inrange(0, 10):
        print"\t\nWRITE YOUR OPERATION"
        code = 'print('
        s = raw_input()
        elements = s.split()

        for element in elements:
            code = code + returnElement(element)           

        code = code + ')'print code
        exec code