How to use Python to convert an octal to a decimal

问题

I have this little homework assignment and I needed to convert decimal to octal and then octal to decimal. I did the first part and can not figure out the second to save my life. The first part went like this:

decimal = int(input("Enter a decimal integer greater than 0: "))

print("Quotient Remainder Octal") 
bstring = " "
while decimal > 0:
    remainder = decimal % 8 
    decimal = decimal // 8 
    bstring = str(remainder) + bstring 
    print ("%5d%8d%12s" % (decimal, remainder, bstring))
print("The octal representation is", bstring)

I read how to convert it here: Octal to Decimal but have no clue how to turn it into code. Any help is appreciated. Thank you.

回答1:

From decimal to octal:

oct(42) # '052'

Octal to decimal

int('052', 8) # 42

Depending if you want to return octal as a string or integer you might want to wrap it in str or int respectively.

回答2:

Someone might find these useful

These first lines take any decimal number and convert it to any desired number base

def dec2base():
a= int(input('Enter decimal number: \t'))
d= int(input('Enter expected base: \t'))
b = ""
while a != 0:
    x = '0123456789ABCDEF'
    c = a % d
    c1 = x[c]
    b = str(c1) + b
    a = int(a // d)
return (b)

The second lines do the same but for a given range and a given decimal

def dec2base_R():
a= int(input('Enter start decimal number:\t'))
e= int(input('Enter end decimal number:\t'))
d= int(input('Enter expected base:\t'))
for i in range (a, e):
    b = ""
    while i != 0:
        x = '0123456789ABCDEF'
        c = i % d
        c1 = x[c]
        b = str(c1) + b
        i = int(i // d)
    return (b)

The third lines convert from any base back to decimal

def todec():
c = int(input('Enter base of the number to convert to decimal:\t')) 
a = (input('Then enter the number:\t ')).upper()
b = list(a)
s = 0
x = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F']
for pos, digit in enumerate(b[-1::-1]):
    y = x.index(digit)
    if int(y)/c >= 1:
            print('Invalid input!!!')
            break
    s =  (int(y) * (c**pos)) + s
return (s)

Note: I also have the GUI version if anyone needs them

回答3:

def decimal_to_octal(num1):
  new_list = []
  while num1 >= 1:
    num1 = num1/8
    splited = str(num1).split('.')
    num1 = int(splited[0])
    appendednum = float('0.'+splited[1])*8
    new_list.append(int(appendednum))
    decimal_to_octal(num1)    
  return "your number in octal: "+''.join(str(v) for v in new_list[::-1])

print(decimal_to_octal(384))

回答4:

def decimalToOctal(num1):
  new_list = []
  while num1 >= 1:
    num1 = num1/8
    splited = str(num1).split('.')
    num1 = int(splited[0])
    appendednum = float('0.'+splited[1])*8
    new_list.append(int(appendednum))
    decimalToOctal(num1)    
  return "your number in octal: "+''.join(str(v) for v in new_list[::-1])

print(decimalToOctal(384))

来源：https://stackoverflow.com/questions/35450560/how-to-use-python-to-convert-an-octal-to-a-decimal