- # convert a decimal (denary, base 10) integer to a binary string (base 2)
- # tested with Python24 vegaseat 6/1/2005
- def Denary2Binary(n):
- '''convert denary integer n to binary string bStr'''
- bStr = ''
- if n < 0: raise ValueError, "must be a positive integer"
- if n == 0: return '0'
- while n > 0:
- bStr = str(n % 2) + bStr
- n = n >> 1
- return bStr
- def int2bin(n, count=24):
- """returns the binary of integer n, using count number of digits"""
- return "".join([str((n >> y) & 1) for y in range(count-1, -1, -1)])
- # this test runs when used as a standalone program, but not as an imported module
- # let's say you save this module as den2bin.py and use it in another program
- # when you import den2bin the __name__ namespace would now be den2bin and the
- # test would be ignored
- if __name__ == '__main__':
- print Denary2Binary(255) # 11111111
- # convert back to test it
- print int(Denary2Binary(255), 2) # 255
- # this version formats the binary
- print int2bin(255, 12) # 000011111111
- # test it
- print int("000011111111", 2) # 255
- # check the exceptions
- print Denary2Binary(0)
- print Denary2Binary(-5) # should give a ValueError
来源: http://www.phpxs.com/code/1005010/