是按正常的手算流程，取余数得来，使用了一个递归,代码如下：
dic_alpha = {10: 'A', 11: 'B', 12: 'C', 13: 'D', 14: 'E', 15: 'F' }
converted_list = []
def convert(num, base):
num = abs(num)
remainder = num % base
if num >= base:
convert(num / base, base)
converted_list.append(remainder)
def format_print(num, base):
if num < 0:
result = '-'
else:
result = ''
convert(num, base)
for item in converted_list:
if item in dic_alpha.keys():
item = dic(item)
result += str(item)
print result