我在2.7中有一個正常工作的貨幣轉換器，但我想確保該程序不會獲取用戶無法處理的數據。如何獲得與案例無關的用戶輸入如果用戶輸入錯誤，如何使程序重新啟動；即休息一下，但是盡管四處尋找并測試了一些方法，但我仍無法弄清楚該如何做。我保留了其余的代碼，因為它與使用預設數字的第一組乘法實際上無關緊要。currency = str(raw_input ("""what currency would you like to covert: GBP, EURO, USD OR YEN?"""))exchange = str(raw_input("""what currency would you like in exchange? : GBP, EURO, USD OR YEN? """))amount = int(input("""how much would you like to convert? """))decision = str(raw_input("""Please enter u for user input exchange rate or s for the preset exchange rate"""))if decision == "u" : user_rate = raw_input("Please enter the current exchange rate") exchange_value = int(amount) * int(user_rate) print ("At the user found exchange rate you will receive",exchange_value,exchange)elif decision == "s" : if currency == "GBP" and exchange == "USD": exchange_value= int(amount) * 1.6048 print ("At the preset exchange rate you will receive",exchange_value,exchange) if currency == "GBP" and exchange == "EUR": exchange_value= int(amount) * 1.2399 print ("At the preset exchange rate you will receive",exchange_value,exchange)
2 回答
繁花不似錦
TA貢獻1851條經驗 獲得超4個贊
這樣的事情將幫助您入門
valid_input = ('EUR', 'GBP', 'USD', 'JPY')
while True:
# Obtain user data
# Make sure all its in caps
currency = currency.upper()
exchange = exchange.upper()
if currency in valid_input and exchange in valid_input:
break
print ("Error Invalid input, try again...")
# Proccess data...
搖曳的薔薇
TA貢獻1793條經驗 獲得超6個贊
1）您可以使用相同的大小寫來比較用戶輸入的字符串
if currency.lower() == 'gbp'
或者
if currency.upper() == 'GBP'
2）您可以在while循環(huán)中運行程序，這樣，如果不滿足條件，則可以continue循環(huán)到下一次迭代（這將從頭開始重新啟動程序）
while True:
# get user input
# validate user input
# if input not valid continue, which will "restart" your program
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