python 2018全国自学考试第4章 第18题 第一次使用def功能

4.18 编写程序提示用户输入美元和人民币之间的汇率。提示用户输入0表示将美元转换为人民币，而1表示将人民币转换为美元。提示用户输入美元或人民币。将其分别转换为人民币或美元

ex_rate_num = eval(input("Enter the exchange rate from dollars to RMB: "))
convert_num = eval(input("Enter 0 to convert dollars to RMB and 1 vice versa: "))


d_int_text = 0
r_int_text = 0
dollars_num = 0
rmb_num = 0
d_message_text = 0
rmb_message_text = 0
amount_num  = 0
if convert_num == 0:
    amount_num = eval(input("Enter the Dollars amount: "))
    d_int_text = "$"
    dollars_num = amount_num * ex_rate_num
    d_message_text = "Yuan"
elif convert_num == 1:
    amount_num = eval(input("Enter the RMB amount: "))
    r_int_text = "￥"
    rmb_num = amount_num // ex_rate_num
    rmb_message_text = "Dollars"
else:
    print("Incorrect input")
print(f"{d_int_text or r_int_text}{amount_num} is {dollars_num or rmb_num} {d_message_text or rmb_message_text}")

问题

1、输入超过1的数值后，还能打印。这个问题是为了满足自由在一个行里显示各种信息的后果。是否可以解决看以后的学习。这次不解决
2、在if前，要对在if中出现的各种变量进行提前赋值。感觉很啰嗦。

以下是第7次该题是写的。感觉很简洁，而这次的设计是整洁了一行麻烦了整个程序

ex_rate_mon = eval(input("Enter the exchange rate from dollars to RMB: "))
con_versa = eval(input("Enter 0 to convert dollars to RMB and 1 vice versa: "))
if con_versa == 0:
    amount = eval(input(f"Enter the dollar amount: "))
    
    amount_1 = round(amount * ex_rate_mon,2)
    print(f"${amount} is {amount_1} yuan")
elif con_versa == 1:
    amount = eval(input(f"Enter the RMB amount: "))
    
    amount_1 = round(amount / ex_rate_mon,2)
    print(f"{amount} yuan is ${amount_1} ")

接下来准备用def来设计这个程序

def rmb_date(amount_num):
    rmb_yuan = amount_num * ex_rate_num
    print(f"${amount_num} is {rmb_yuan} yuan")


def dollars_date(amount_num):
    dollars_num = amount_num // ex_rate_num
    print(f"￥{amount_num} is {dollars_num} dollars")


ex_rate_num = eval(input("Enter the exchange rate from dollars to RMB: "))
convert_num = input("Enter 0 to convert dollars to RMB and 1 vice versa: ")

try:

    if convert_num == 0:
        amount_num = eval(input("Enter the Dollars: "))
        rmb_date(amount_num)

    elif convert_num == 1:
        amount_num = eval(input("Enter the RMB: "))
        dollars_date(amount_num)
    else:
        print("Incorrect input")

except ValueError:
    print("Input integer and float, Don't input text Thank you!")

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