python 中的進位制轉換 整理
阿新 • • 發佈:2019-01-06
工作中經常需要用到進位制轉換, 一直對這方面有一些模糊, 終於有時間把這方面整理一下了.
常用的進位制: 二進位制bin(), 八進位制oct(), 十進位制int(), 十六進位制hex()
下面我採用python3.6中的原始碼進行解釋, 來自python中的builtins.py
bin(x) 將一個整型數字轉換為二進位制字串
def bin(*args, **kwargs): # NOTE: unreliably restored from __doc__ """ Return the binary representation of an integer. >>> bin(2796202) '0b1010101010101010101010' """ pass
oct() 將一個整型數字轉換為一個八進位制字串
def oct(*args, **kwargs): # real signature unknown; NOTE: unreliably restored from __doc__
"""
Return the octal representation of an integer.
>>> oct(342391)
'0o1234567'
"""
pass
int() 將一個數字或者字串轉換為一個整型數字
def __init__(self, x, base=10): # known special case of int.__init__ """ int(x=0) -> integer int(x, base=10) -> integer Convert a number or string to an integer, or return 0 if no arguments are given. If x is a number, return x.__int__(). For floating point numbers, this truncates towards zero. If x is not a number or if base is given, then x must be a string, bytes, or bytearray instance representing an integer literal in the given base. The literal can be preceded by '+' or '-' and be surrounded by whitespace. The base defaults to 10. Valid bases are 0 and 2-36. Base 0 means to interpret the base from the string as an integer literal. >>> int('0b100', base=0) 4 # (copied from class doc) """ pass
hex() 將一個整型數字轉換為一個十六進位制字串
def hex(*args, **kwargs): # NOTE: unreliably restored from __doc__
"""
Return the hexadecimal representation of an integer.
>>> hex(12648430)
'0xc0ffee'
"""
pass
下面是一個不同進位制之間的相互轉換:
要注意的是內建的bin() oct() hex() 的返回值均為 字串的形式, 而且前面分別帶有0b 0o 0x 的字首;
示例如下:
>>> bin(15)
'0b1111'
>>> bin(2)
'0b10'
>>> oct(16)
'0o20'
>>> oct(64)
'0o100'
>>> hex(16)
'0x10'
>>> hex(256)
'0x100'
實際工作中我們可能需要自己寫進位制轉換, 因為自帶的返回值含有字首;
import os, sys
baseNum = ['1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E']
# baseNum = [str(x) for x in range(1,10)] + [chr(x) for x in range(ord('A'), ord("F")) ]
# 二進位制轉為 十進位制
def bin2dec(strNum):
return str(int(strNum,2))
print(bin2dec("11")) # 3
# 八進位制轉為十進位制
def oct2dec(strNum):
return str(int(strNum,8))
print(oct2dec('11')) # 9
# 十六進位制轉為十進位制
def hex2dec(strNum):
return str(int(strNum,16))
print(hex2dec('11')) # 17
# 十進位制轉為二進位制
def dec2bin(strNum):
num = int(strNum)
bitList = []
while num != 0:
num, res = divmod(num,2)
bitList.append(base[res])
return ''.join([str(i) for i in bitList][::-1])
print(dec2bin("15"))
# 八進位制 和 十六進位制轉二進位制, 可以採用先轉為十進位制, 後再轉為二進位制
# 同理:
# 十進位制轉為八進位制
def dec2oct(strNum):
num = int(strNum)
bitList = []
while num != 0:
num, res = divmod(num,8)
bitList.append(base[res])
return ''.join([str(i) for i in bitList][::-1])
print(dec2oct("16"))
# 十進位制轉為十六進位制, 只要將上面程式碼中的 divmod(num,8) 改為 divmod(num,16)
進位制轉換, 如果直接轉一次不能完成的話, 那就先轉成其他進位制, 間接地轉.