python十进制转二进制转换_python十进制转二进制，可指定位数

# 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__ names