The first list has all the units referred to in the numerator, the second lists the units referred to in the denominator I think you've already done most of the function, but I don't understand why it doesn't meet the requirements, which are to simplify the fraction as much as possible, for example when the denominator and the numerator are equal it is not returning (['1'], ['1']) and other example is when the the function in one for the teste returns (['1', '1', 's'], ['s']) instead of (['1'], ['1']).

def canonical(unit):
    numerador = unit[0]
    denominador = unit[1]
    numerador.sort()
    denominador.sort()
    
    lstNumerador = numerador
    lstDenominador = denominador
    
    for i in numerador:
        for j in denominador:
            if i == j:
                lstNumerador.remove(i)
                lstDenominador.remove(j)
                
    
    if lstNumerador.count('1') > 0:
        lstNumerador.remove('1')
        
    if lstDenominador.count('1') > 0:
        lstDenominador.remove('1')
        
    if len(lstNumerador) == 0:
        lstNumerador.append('1')
        
    if len(lstDenominador) == 0:
        lstDenominador.append('1')
        
    unit = (lstNumerador, lstDenominador)
    return unit

#what i expect

unit = (['kg', 'm', 'm', 's'], ['m', 's', 's'])
print(canonical(unit))
#(['kg', 'm'], ['s'])
unit = (['kg', 'm', 'm', 's'], ['s', 'm', 'm', 'kg'])
print(canonical(unit))
#(['1'], ['1'])
unit = (['s', 'kg', 'm', '1'], ['1', '1'])
print(canonical(unit))
#(['kg', 'm', 's'], ['1'])
unit = (['1', 'm', 's', '1', '1'], ['m', 's'])
print(canonical(unit))
#(['1'], ['1'])
unit = (['kg', 'm', 'm'], ['kg', 'm', 'm'])
print(canonical(unit))
#(['1'], ['1'])

#what i received
(['kg', 'm'], ['s'])
(['m', 's'], ['m', 's'])
(['kg', 'm', 's'], ['1'])
(['1', '1', 's'], ['s'])
(['m'], ['m'])

CodePudding user response：

See copy below. I created a deepcopy of your unit so it is impregnable to iterate/remove and also corrected the logic which was wrong in a few places. This gives the output you expect.

import copy

def canonical(unit):
    numerador = unit[0]
    denominador = unit[1]
    numerador.sort()
    denominador.sort()
    
    lstNumerador = copy.deepcopy(numerador)
    lstDenominador = copy.deepcopy(denominador)
    
    for i in numerador:
        for j in denominador:
            if (i in lstNumerador) and (i in lstDenominador):
                    lstNumerador.remove(i)
                    lstDenominador.remove(i)
                
    
    while lstNumerador.count('1') > 1:
        lstNumerador.remove('1')
        
    while lstDenominador.count('1') > 1:
        lstDenominador.remove('1')
        
    if len(lstNumerador) == 0:
        lstNumerador.append('1')
        
    if len(lstDenominador) == 0:
        lstDenominador.append('1')
        
    unit = (lstNumerador, lstDenominador)
    return unit

unit1 = (['kg', 'm', 'm', 's'], ['m', 's', 's'])

unit2 = (['kg', 'm', 'm', 's'], ['s', 'm', 'm', 'kg'])

unit3 = (['s', 'kg', 'm', '1'], ['1', '1'])

unit4 = (['1', 'm', 's', '1', '1'], ['m', 's'])

unit5 = (['kg', 'm', 'm'], ['kg', 'm', 'm'])

units = [unit1, unit2, unit3, unit4, unit5]

for entry in units:
    print(canonical(entry))

output:

(['kg', 'm'], ['s'])
(['1'], ['1'])
(['kg', 'm', 's'], ['1'])
(['1'], ['1'])
(['1'], ['1'])

CodePudding user response：

Note: i left denominator empty instead of adding one to it

def canonical(unit):
    numerador = sorted([i for i in unit[0] if i!='1'])
    denominador = sorted([i for i in unit[1] if i!='1'])


    numCount= {i : numerador.count(i)-denominador.count(i) for i in set(numerador  denominador)}
    
    numerador=denominador= []

    for num,count in numCount.items():
        if count>0:
            numerador =[num]*count
        elif count<0:
            denominador = [num]*-count

    if len(numerador) == 0:
        numerador=['1']
    if len(denominador) == 0:
        denominador=['1']
    
    return (numerador, denominador)