python多if/elif/else語句並僅顯示用戶選擇

-4

使用python 2.7.5，解決編程類問題，其中訂單總額被添加到運輸成本，價格被設置爲運送到美國和加拿大，我寫有代碼運送到美國但需要更改值，因此如果用戶選擇加拿大，則將不同的一組值應用於訂單總額。加拿大運費：8.00小於50.0，12.0超過50.01 - 100.0，15.0 100.01 - 150.0，我需要一種方法，在下面的代碼在美國國內運費替換這些值：python多if/elif/else語句並僅顯示用戶選擇

user_order = float(input("how much is your order? ")) 
user_ship_area = raw_input('Are you shipping to the US or Canada?') 

if user_order < 50.00 and user_ship_area == "US": #start selection with user order and shipping area. 
    #User would be given price for shipping according to order cost 
    print 'you must pay $6.00 for shipping ' #user order less than 50$ = 64 for shipping. 
    user_order = user_order + 6.0 

elif user_order <100.0> 50.01 and user_ship_area == "US": #must include range of numbers, if user order is over 50.01 but under 100.0 
    print 'you must pay $9.00 for shipping' #they must pay 9.00 for shipping. 
    user_order = user_order + 9.0 

elif user_order <150.0> 100.01 and user_ship_area == "US": #if user order is over 100.01$ but under 150$ 
    print 'you must pay $12.00 for shipping '#12.00$ will be charged for shipping 
    user_order = user_order + 12.0 
else: 
    print 'congratulations you qualify for free shipping' #since it works by checking each elif, it goes to else 


print "your order total is", user_order 

#need to create option for shipping to Canada, the prices are different. 
#how to repeat the above code but for different values if the user selects Canada.

來源

2013-10-14 JuanB457

請正確縮進您的代碼。 – thefourtheye

當你看到這樣的信息

user_order <100.0> 50.01

到Python它會評估它像這樣

user_order < 100.0 and 100.0 > 50.01

但是，這不是我們想。我們要覈對一下

user_order < 100.0 and user_order > 50.01

所以正確的方式來寫的條件將是

50.01 < user_order < 100.0

建議：

你不必使用
```
float(input("how much is your order? ")) 
```
要麼
```
float(raw_input("how much is your order? ")) 
```
或
```
input("how much is your order? ") # Don't use this 
```
因爲input將在內部做eval(whatever user inputs)。這將自動找到正確的數據類型。注意在Python2中不要使用input，它可能導致潛在的安全問題。（感謝Matthias指出它）
無論何時您發佈代碼（甚至更好，寫作時）嘗試並正確縮進代碼。這將使調試更容易。

來源

2013-10-14 02:53:54 thefourtheye

在Python 2中使用'input'是definitley的一個壞主意。「eval」的內部使用不是一個優勢，而是一個安全漏洞。 – Matthias

@Matthias謝謝。忘了提到這一點。現在，我將其包含在答案中。 – thefourtheye

你的布爾表達式不正確; Python自然會將它們鏈接起來，所以它們必須以這種方式寫。

50.01 < user_order < 100.0

來源

2013-10-14 02:47:48

值得注意的是，在OPs代碼中的比較是有效的，只是沒有做他們所期望的。 'user_order < 100.0 > 50.01'將被分解爲'user_order <100.0 && 100.0> 50.01'，它等於'user_order <100。0 && True' Plus，因爲python條件會從頭到尾被解釋，即使表達式很奇怪，它們仍然是正確的。 – 2013-10-14 02:56:34

@LegoStormtroopr'&&'不是Python中的合法運算符 – SethMMorton

-1

它看起來像程序重複兩次。我清理了觸摸和這個工程：

user_order = float(input("how much is your order? ")) 
total = user_order 

if user_order < 50.00: 
    #User would be given price for shipping according to order cost 
    print 'you must pay $6.00 for shipping ' 
    total = user_order + 6.0 

elif user_order <100.0> 50.01: 
    print 'you must pay $9.00' #they must pay 9.00 for shipping. 
    total = user_order + 9.0 

elif user_order <150.0> 100.01: #if user order is over 100.01$ but under 150$ 
    print 'you must pay $12.00 for shipping '#12.00$ will be charged for shipping 
    total = user_order + 12.0 
else: 
    print 'congratulations you qualify for free shipping'         
    #this is where the confusion occurs, I need to have the option to ship to US or Canada    
    #the values for shipping to Canada since its different for shipping to that country 

user_ship_area = raw_input('Are you shipping to the US or Canada?') 
if user_ship_area != 'US': 
    print 'confirmed, we will ship to Canada ' 

else: 
    print "confirmed, we will ship to the United States" 

print "your order total is %s"%(total)

來源

2013-10-14 02:52:36

你能解釋一下你「如何清理它」嗎？ – 2013-10-14 02:54:01

你擁有的布爾表達式並沒有達到你期望的效果 – SethMMorton

-1

這是正確的形式，請注意如何把條件放在if-else在Python中。

user_order = float(input("how much is your order? ")) 

if user_order < 50.00: 
    #User would be given price for shipping according to order cost 
    print 'you must pay $6.00 for shipping ' 
    user_order = user_order + 6.0 

elif user_order < 100.0 and user_order > 50.01: 
    print 'you must pay $9.00' #they must pay 9.00 for shipping. 
    user_order = user_order + 9.0 

elif user_order < 150.0 and user_order > 100.01: #if user order is over 100.01$ but under 150$ 
    print 'you must pay $12.00 for shipping '#12.00$ will be charged for shipping 
    user_order = user_order + 12.0 
else: 
    print 'congratulations you qualify for free shipping'         
#this is where the confusion occurs, I need to have the option to ship to US or Canada    
#the values for shipping to Canada since its different for shipping to that country 

user_ship_area = raw_input('Are you shipping to the US or Canada?') 
if user_ship_area != 'US': 
    print 'confirmed, we will ship to Canada ' 

else: 
    print "confirmed, we will ship to the United States" 
    print "your order total is", user_order 

if user_order < 50.00: 
#User would be given price for shipping according to order cost 
    print 'you must pay $8.00 for shipping ' 
    user_order = user_order + 8.0 

elif user_order < 100.0 and user_order > 50.01: 
    print 'you must pay $12.00' 
    user_order = user_order + 12.0 

elif user_order < 150.0 and user_order > 100.01: 
    print 'you must pay $15.00 for shipping ' 
    user_order = user_order + 15.0 
else: 
    print 'congratulations you qualify for free shipping' 
#the final output needs to be the user_order + the amount its shipping to depending on 
#the country

來源

2013-10-14 03:03:54

這並沒有解決邏輯重複兩次的問題，並且關於python如何鏈接布爾運算符是錯誤的。 – 2013-10-14 03:36:15

python多if/elif/else語句並僅顯示用戶選擇

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