dbUnit = [
         ['C', 'Temperature', 1.0, 0.0],
         ['K', 'Temperature', 1.0, 273.15],
         ['F', 'Temperature', 1.8, 32.0],
         ['R', 'Temperature', 1.8, 491.67],
         ['kPa', 'Pressure',  1.0, 0.0],
         ['MPa', 'Pressure',  0.001, 0.0],
         ['bar', 'Pressure',  0.01, 0.0],
         ['N/m2', 'Pressure', 1000.0, 0.0],
         ['atm', 'Pressure', 0.009869233, 0.0],
         ['at', 'Pressure', 0.01019716, 0.0],
         ['kg/cm2', 'Pressure', 0.01019716, 0.0],
         ['psia', 'Pressure', 0.1450377, 0.0],
         ['lbf/ft2', 'Pressure', 20.88543, 0.0],
         ['torr', 'Pressure', 7.500615, 0.0],
         ['kPag', 'Pressure', 1.0, -101.325],
         ['MPag', 'Pressure', 0.001, -0.101325],
         ['bar_g', 'Pressure', 0.01, -1.01325],
         ['N/m2_g', 'Pressure', 1000.0, -101325.0],
         ['atm_g', 'Pressure', 0.009869, -1.0],
         ['ate', 'Pressure', 0.01019716, -1.033227],
         ['kg/cm2_g', 'Pressure', 0.01019716, -1.033227],
         ['psig', 'Pressure', 0.1450377, -14.696],
         ['lbf/ft2_g', 'Pressure', 20.88543, -2116.216],
         ['torr_g', 'Pressure', 7.500615, -760.0],
         ]

def loadUnit(search):
    for i in range(len(dbUnit)):
        if dbUnit[i][0] == search:
            UnitGroup = dbUnit[i][1]
            UnitScale = float(dbUnit[i][2])
            UnitOffset = float(dbUnit[i][3])

    return UnitGroup, UnitScale , UnitOffset

def unitconv(number, Unit_old, Unit_new):
    
    Group_old, Scale_old, Offset_old = loadUnit(Unit_old)
    Group_new, Scale_new, Offset_new = loadUnit(Unit_new)

    if Scale_old == 0 or Group_old != Group_new: 
        return None

    return ((number - Offset_old) / Scale_old) * Scale_new + Offset_new

print(unitconv(50, "C", "R")) # 50 C = 581.67 R
print(unitconv(10, "bar_g", "kPa")) # 10 bar_g = 1101.325 kPA