十进制转二进制

bin = lambda n : (n > 0) and (bin(n / 2) + str(n % 2)) or ''

或者

 

#!/usr/bin/python

def bin(x):
        result = ''
        x = int(x)
        while x > 0:
                mod = x % 2
                x /= 2
                result = str(mod) + result
        return result