Python允许从给定基数的字符串中轻松创建一个整数
int(str, base).
我想执行相反的操作:从一个整数创建一个字符串， 例如，我想要一些函数int2base(num, base)，这样:
int(int2base(x, b), b) == x
函数名/参数的顺序并不重要。
对于int()将接受的任何以b为底的数字x。
这是一个很容易写的函数:事实上，它比在这个问题中描述它更容易。然而，我觉得我一定是错过了什么。
我知道函数bin, oct, hex，但我不能使用它们的几个原因:
这些函数在旧版本的Python中不可用，我需要与(2.2)兼容 我想要一个通解对于不同的碱都可以用同样的方式表示 我想允许2 8 16以外的底数
相关的
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当前回答
def dec_to_radix(input, to_radix=2, power=None):
if not isinstance(input, int):
raise TypeError('Not an integer!')
elif power is None:
power = 1
if input == 0:
return 0
else:
remainder = input % to_radix**power
digit = str(int(remainder/to_radix**(power-1)))
return int(str(dec_to_radix(input-remainder, to_radix, power+1)) + digit)
def radix_to_dec(input, from_radix):
if not isinstance(input, int):
raise TypeError('Not an integer!')
return sum(int(digit)*(from_radix**power) for power, digit in enumerate(str(input)[::-1]))
def radix_to_radix(input, from_radix=10, to_radix=2, power=None):
dec = radix_to_dec(input, from_radix)
return dec_to_radix(dec, to_radix, power)
其他回答
我让函数这样做。在windows 10, python 3.7.3上运行良好。
def number_to_base(number, base, precision = 10):
if number == 0:
return [0]
positive = number >= 0
number = abs(number)
ints = [] # store the integer bases
floats = [] # store the floating bases
float_point = number % 1
number = int(number)
while number:
ints.append(int(number%base))
number //= base
ints.reverse()
while float_point and precision:
precision -= 1
float_point *= base
floats.append(int(float_point))
float_point = float_point - int(float_point)
return ints, floats, positive
def base_to_str(bases, string="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"):
"""bases is a two dimension list, where bases[0] contains a list of the integers,
and bases[1] contains a list of the floating numbers, bases[2] is a boolean, that's
true when it's a positive number
"""
ints = []
floats = []
for i in bases[0]:
ints.append(string[i])
for i in bases[1]:
floats.append(string[i])
if len(bases[1]) > 0:
return (["-", ""][bases[2]] + "".join(ints)) + "." + ("".join(floats))
else:
return (["-", ""][bases[2]] + "".join(ints))
例子:
>>> base_to_str(number_to_base(-6.252, 2))
'-110.0100000010'
一个递归的解决方案。当然，这对负二进制值不起作用。您需要实现Two's Complement。
def generateBase36Alphabet():
return ''.join([str(i) for i in range(10)]+[chr(i+65) for i in range(26)])
def generateAlphabet(base):
return generateBase36Alphabet()[:base]
def intToStr(n, base, alphabet):
def toStr(n, base, alphabet):
return alphabet[n] if n < base else toStr(n//base,base,alphabet) + alphabet[n%base]
return ('-' if n < 0 else '') + toStr(abs(n), base, alphabet)
print('{} -> {}'.format(-31, intToStr(-31, 16, generateAlphabet(16)))) # -31 -> -1F
def base_changer(number,base):
buff=97+abs(base-10)
dic={};buff2='';buff3=10
for i in range(97,buff+1):
dic[buff3]=chr(i)
buff3+=1
while(number>=base):
mod=int(number%base)
number=int(number//base)
if (mod) in dic.keys():
buff2+=dic[mod]
continue
buff2+=str(mod)
if (number) in dic.keys():
buff2+=dic[number]
else:
buff2+=str(number)
return buff2[::-1]
我提出了一个“非优化”的2到9基的解决方案:
def to_base(N, base=2):
N_in_base = ''
while True:
N_in_base = str(N % base) + N_in_base
N //= base
if N == 0:
break
return N_in_base
这个解决方案不需要反转最终结果，但实际上并没有优化。请参考以下答案了解原因:https://stackoverflow.com/a/37133870/7896998
http://code.activestate.com/recipes/65212/
def base10toN(num,n):
"""Change a to a base-n number.
Up to base-36 is supported without special notation."""
num_rep={10:'a',
11:'b',
12:'c',
13:'d',
14:'e',
15:'f',
16:'g',
17:'h',
18:'i',
19:'j',
20:'k',
21:'l',
22:'m',
23:'n',
24:'o',
25:'p',
26:'q',
27:'r',
28:'s',
29:'t',
30:'u',
31:'v',
32:'w',
33:'x',
34:'y',
35:'z'}
new_num_string=''
current=num
while current!=0:
remainder=current%n
if 36>remainder>9:
remainder_string=num_rep[remainder]
elif remainder>=36:
remainder_string='('+str(remainder)+')'
else:
remainder_string=str(remainder)
new_num_string=remainder_string+new_num_string
current=current/n
return new_num_string
这是来自同一个链接的另一个
def baseconvert(n, base):
"""convert positive decimal integer n to equivalent in another base (2-36)"""
digits = "0123456789abcdefghijklmnopqrstuvwxyz"
try:
n = int(n)
base = int(base)
except:
return ""
if n < 0 or base < 2 or base > 36:
return ""
s = ""
while 1:
r = n % base
s = digits[r] + s
n = n / base
if n == 0:
break
return s
