Python实现：十进制数与（2~16进制数）之间的互相转换

# 将X进制转为int十进制的功能函数：(乘X次方各位数的加和法)
def XToInt(strNum,X):
    sum = 0
    strNum = strNum.lstrip("0") #去掉开始的0（前导零）
    length = len(strNum)
    for i in range(length):
        sum += ABCToNum(strNum[i])*(X**(length-i-1))
    return sum

# 将int十进制转为Y进制的功能函数：(除Y取余法)
def intToY(num,Y):
    res = ""
    while (num!=0):
        # temp=
        # temp=
        res = str(NumToABC(num%Y))+res
        num = num//Y #取商
    # res = int(res)
    res.upper()
    return res

#  辅助功能函数
def ABCToNum(char):
    if char in "0123456789":
        return int(char)
    if char in "Aa" :
        return 10
    if char in "Bb":
        return 11
    if char in "Cc" :
        return 12
    if char in "Dd":
        return 13
    if char in "Ee" :
        return 14
    if char in "Ff":
        return 15
#  辅助功能函数
def NumToABC(intN):
    if intN in [0,1,2,3,4,5,6,7,8,9]:
        return intN
    if intN ==10 :
        return 'A'
    if intN ==11 :
        return 'B'
    if intN ==12 :
        return 'C'
    if intN ==13 :
        return 'D'
    if intN ==14 :
        return 'E'
    if intN ==15 :
        return 'F'

#  辅助功能函数
def ABCToNum(char):
    if char in "0123456789":
        return int(char)
    if char in "Aa" :
        return 10
    if char in "Bb":
        return 11
    if char in "Cc" :
        return 12
    if char in "Dd":
        return 13
    if char in "Ee" :
        return 14
    if char in "Ff":
        return 15
#  辅助功能函数
def NumToABC(intN):
    if intN in [0,1,2,3,4,5,6,7,8,9]:
        return intN
    if intN ==10 :
        return 'A'
    if intN ==11 :
        return 'B'
    if intN ==12 :
        return 'C'
    if intN ==13 :
        return 'D'
    if intN ==14 :
        return 'E'
    if intN ==15 :
        return 'F'

# 将X进制转为int十进制的功能函数：(乘X次方各位数的加和法)
def XToInt(strNum,X):
    sum = 0
    strNum = strNum.lstrip("0") #去掉开始的0（前导零）
    length = len(strNum)
    for i in range(length):
        sum += ABCToNum(strNum[i])*(X**(length-i-1))
    return sum
# 将int十进制转为Y进制的功能函数：(除Y取余法)
def intToY(num,Y):
    res = ""
    while (num!=0):
        # temp=
        # temp=
        res = str(NumToABC(num%Y))+res
        num = num//Y #取商
    # res = int(res)
    res.upper()
    return res

def NumberSystemConversion():
    X,strInput,Y = input().split()
    intA = XToInt(strInput,int(X))
    outB = intToY(intA,int(Y))
    print(outB)
NumberSystemConversion()