交互式（无精美UI）房贷计算器上线啦啦啦啊啦啦啦。。。

import math
import random


def input_limit(input_name, input_range):
    if input_range[0] <= input_name <= input_range[-1]:
        return True
    else:
        print('请输入在', input_range[0],'和', input_range[-1], '之间的数值')
        return False


def bank_loan():
    print('*'*20+'欢迎使用房贷计算器！'+'*'*20)
    try:
        while True:
            loan_base = float(input('您购房共贷款金额(万元)：'))
            if input_limit(loan_base, [0,99999999999]):
                print('*'*15, loan_base, '万元'+'*'*5)
                break
        while True:
            loan_rate = float(input('您的贷款年利率是（%）：'))
            if input_limit(loan_rate, [0,100]):
                print('*'*15, loan_rate,'%'+'*'*5)
                break
        while True:
            loan_way = int(input('您的还贷方式是：1.等额本金/2.等额本息'))
            if input_limit(loan_way, [1,2]):
                print('*' * 15, '等额本金'+'*' * 5) if loan_way == 1 else print('*'*15+'等额本息'+'*'*5)
                break
        while True:
            loan_term = int(input('您的还款期限（年）是：'))
            if input_limit(loan_term, [1,140]):
                print('*'*15, loan_term,'年'+'*'*5)
                break
    except(ValueError, EOFError, TypeError):
        print('请输入正确的数字格式')
    else:
        loan_base = loan_base*10000
        loan_rate = loan_rate/100
        print('您一共贷款人民币', loan_base, '元，期限是', loan_term, '年。')
        print('您选择的还贷方式是：')
        print('等额本金') if loan_way == 1 else print('等额本息')
        print('以下是系统为您计算的每月预还款数额，请查收：')
        if loan_way == 1:
            n=1
            loan_sum_1 = 0
            while n <= 12*loan_term:
                base_1 = loan_base/(12*loan_term)
                loan_n = ((loan_base - base_1*(n-1))*loan_rate/12)
                print('第',n,'个月：您已还款', loan_sum_1,'元，您本月需还款：',loan_n + base_1, '元，其中包含本月利息', loan_n ,'元；')
                loan_sum_1 = loan_sum_1 + loan_n + base_1
                n = n+1
            print('您共还款', loan_sum_1,'元，历时',n-1,'个月，总利息为：',loan_sum_1 - loan_base,'元，月平均利息为',(loan_sum_1 - loan_base)/(n-1),'元')
        else:
            k = 1
            loan_sum_2 = 0
            base_2_rate = 0
            rate = loan_rate/12
            term = 12*loan_term
            base_2 = (loan_base*rate*math.pow((1+rate),term))/(math.pow((1+rate),term)-1)
            while k <= term:
                base_2_rate = loan_base*rate*pow((1+rate),k) - base_2*(pow((1+rate),k)-1)
                print('第',k,'个月：您已还款', loan_sum_2,'元，您本月需还款：',base_2, '元，其中包含本月利息', base_2_rate ,'元；')
                loan_sum_2 = loan_sum_2 + base_2
                k = k+1
            print('您共还款', loan_sum_2, '元，历时', k - 1, '个月，总利息为：', loan_sum_2 - loan_base, '元，月平均利息为',
                  (loan_sum_2 - loan_base) / (k - 1), '元')
    bank_loan()


bank_loan()