我正在编写一个代码来检查一个数字在2-10中是回文多少次。有没有将数字转换成不同基的python函数?
我已经尝试过手动创建一个函数,但是它太慢了。
baseChars="0123456789"
def toBase(n, b):
return "0" if not n else toBase(n//b, b).lstrip("0") + baseChars[n%b]
我期望toBase函数返回所有基数从2-10表示的数字。我想避免NumPy
发布于 2019-07-10 16:50:37
我认为在标准库中没有任何一个函数可以做到这一点。但是在为我自己的一个类编写一个不同的项目时,我必须解决这类问题,我的解决方案如下所示:
def _base(decimal, base):
"""
Converts a number to the given base, returning a string.
Taken from https://stackoverflow.com/a/26188870/2648811
:param decimal: an integer
:param base: The base to which to convert that integer
:return: A string containing the base-base representation of the given number
"""
li = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
other_base = ""
while decimal != 0:
other_base = li[decimal % base] + other_base
decimal = decimal // base
if other_base == "":
other_base = "0"
return other_base
def palindromes(num, bases=range(2, 11)):
"""
Checks if the given number is a palindrome in every given base, in order.
Returns the sublist of bases for which the given number is a palindrome,
or an empty list if it is not a palindrome in any base checked.
:param num: an integer to be converted to various bases
:param bases: an iterable containing ints representing bases
"""
return [i for i in bases if _base(num, i) == _base(num, i)[::-1]]
(最后一条语句(展开for
循环)的一个不那么简洁的版本如下所示):
r = []
for i in bases:
b = _base(num, i)
if b == b[::-1]:
r.append(i)
return r
在您的情况下,如果您只想要一个以不同基表示整数的列表,那么代码就会更简单:
reps = {b: _base(num, b) for base in range(2, 11)}
会产生一个base : representation in that base
的片段。例如,如果num = 23
{2: '10111',
3: '212',
4: '113',
5: '43',
6: '35',
7: '32',
8: '27',
9: '25',
10: '23'}
发布于 2019-07-10 16:38:02
这在NumPy中可以通过base_repr()
获得。
import numpy as np
[np.base_repr(100, base) for base in range(2,11)]
结果:
['1100100', '10201', '1210', '400', '244', '202', '144', '121', '100']
发布于 2019-07-10 17:20:04
尝尝这个
def rebase( value, new_base ):
res = ""
while value > 0:
res = str( value % new_base ) + res
value = int( value / new_base )
return res
https://stackoverflow.com/questions/56975024
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