# global definition
# base = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F]
base = [str(x) for x in range(10)] + [ chr(x) for x in range(ord('A'),ord('A')+6)]

# 二進制 to 十進制: int(str,n=10)
def bin2dec(string_num):
    return str(int(string_num, 2))

# 十六進制 to 十進制
def hex2dec(string_num):
    return str(int(string_num.upper(), 16))

# 十進制 to 二進制: bin()
def dec2bin(string_num):
    num = int(string_num)
    mid = []
    while True:
        if num == 0: break
        num,rem = divmod(num, 2)
        mid.append(base[rem])
    return ''.join([str(x) for x in mid[::-1]])

# 十進制 to 八進制: oct()
# 十進制 to 十六進制: hex()
def dec2hex(string_num):
    num = int(string_num)
    mid = []
    while True:
        if num == 0: break
        num,rem = divmod(num, 16)
        mid.append(base[rem])
    return ''.join([str(x) for x in mid[::-1]])

# 十六進制 to 二進制: bin(int(str,16))
def hex2bin(string_num):
    return dec2bin(hex2dec(string_num.upper()))

# 二進制 to 十六進制: hex(int(str,2))
def bin2hex(string_num):
    return dec2hex(bin2dec(string_num))