blocks|key|1794223|text|问题出在哪里？这段代码运行得很好。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1794224|#Create+a+list+for+when+they+select+the+computer+they+want
ComputerList+=+["(1)Home+Basic+$900",+"(2)Office+$1200",+"(3)Gamer+$1500",+"(4)Studio+$2200",+"test+(5)"]
#Ask+them+what+they+want+and+repeat+if+left+blank
while+True:
++++print(ComputerList)
++++ComputerChoice+=+input("What+computer+would+you+like+to+buy?(Use+the+number+beside+it+1-%25s):+"+%25+len(ComputerList))
++++try:
++++++++ComputerChoice_int+=+int(ComputerChoice)+-+1
++++++++if+not+-1+<+ComputerChoice_int+<+len(ComputerList):
++++++++++++raise+ValueError
++++++++print("ok")
++++++++break
++++except+ValueError:
++++++++print("Something+went+bad+:/\n")|code-block|syntax|javascript|1794225|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

What is the problem ? This code works perfectly.

<pre><code>#Create a list for when they select the computer they want
ComputerList = ["(1)Home Basic $900", "(2)Office $1200", "(3)Gamer $1500", "(4)Studio $2200", "test (5)"]
#Ask them what they want and repeat if left blank
while True:
 print(ComputerList)
 ComputerChoice = input("What computer would you like to buy?(Use the number beside it 1-%s): " % len(ComputerList))
 try:
 ComputerChoice_int = int(ComputerChoice) - 1
 if not -1 &lt; ComputerChoice_int &lt; len(ComputerList):
 raise ValueError
 print("ok")
 break
 except ValueError:
 print("Something went bad :/\n")
</code></pre>

blocks|key|1794230|text|你可以这样做，使用int(input())会让一切变得更好%2B你不需要排除错误。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1794231|ComputerList+=+["(1)Home+Basic+$900",+"(2)Office+$1200",+"(3)Gamer+$1500",+"(4)Studio+$2200"]

while+True:
++++ComputerChoice+=+int(input("What+computer+would+you+like+to+buy?(Use+the+number+beside+it+1-4):+"))

++++if+ComputerChoice+not+in+range(1,5):
++++++++print("invalid+input")
++++else:
++++++++print("You+selected+{}".format(ComputerList[ComputerChoice-1]))
++++++++#+Do+whatever+here|code-block|syntax|javascript|1794232|entityMap^0|9|C|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

You could do something like this, using <code>int(input())</code> makes everything a lot nicer + you don't have to except errors.

<pre><code>ComputerList = ["(1)Home Basic $900", "(2)Office $1200", "(3)Gamer $1500", "(4)Studio $2200"]

while True:
 ComputerChoice = int(input("What computer would you like to buy?(Use the number beside it 1-4): "))

 if ComputerChoice not in range(1,5):
 print("invalid input")
 else:
 print("You selected {}".format(ComputerList[ComputerChoice-1]))
 # Do whatever here
</code></pre>

blocks|key|1579198|text|它崩溃是因为你没有捕获大于4的输入的子句。它只会在字段不能转换为整数的情况下引发错误。现在您可以硬编码4+in，但更可靠的方法是使用列表的长度。如果您添加或删除计算机，这将使您的代码更容易更新。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1579199|这就是我要做的：|1579200|ComputerList+=+["(1)Home+Basic+$900",+"(2)Office+$1200",+"(3)Gamer+$1500",+"(4)Studio+$2200"]

max_integer+=+len(ComputerList)
status+=+False+
while+status+==+False:
+++try:
++++++Choice+=+int(input("enter+your+choice"))
++++++if+0+<+Choice+<=+max_integer:
+++++++++status+=+True
+++except+ValueError:
++++++print('input+is+invalid')
++++++pass|code-block|syntax|javascript|1579201|这是可以缩短的，但我把它画了一点，这样你就能明白发生了什么。|1579202|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|O|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Its crashing because you have no clause to catch input greater than 4. Its only raising an error if the field is not convertible to an integer. Now you could hardcode the 4 in, but a more reliable method is to use the length of the list. This makes your code more easy to update if you add or remove computers. 

Heres what I would do:

<pre class="lang-py prettyprint-override"><code>ComputerList = ["(1)Home Basic $900", "(2)Office $1200", "(3)Gamer $1500", "(4)Studio $2200"]

max_integer = len(ComputerList)
status = False 
while status == False:
 try:
 Choice = int(input("enter your choice"))
 if 0 &lt; Choice &lt;= max_integer:
 status = True
 except ValueError:
 print('input is invalid')
 pass
</code></pre>

This can be shortened up but I drew it out a bit so you understand whats happening

blocks|key|1579215|text|现在发生的情况是，您只捕获了字符串或空值之类的ValueError。数字4不是错误，因为4是一个整数。如果你想处理ValueError和IndexError，你需要这样做：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1579216|#Create+a+list+for+when+they+select+the+computer+they+want
ComputerList+=+["(1)Home+Basic+$900",+"(2)Office+$1200",+"(3)Gamer+$1500",+"(4)Studio+$2200"]
#Ask+them+what+they+want+and+repeat+if+left+blank
while+True:
++++ComputerChoice+=+input("What+computer+would+you+like+to+buy?(Use+the+number+beside+it+1-4):+")
++++print("")
++++try:
++++++++ComputerChoice_int+=+int(ComputerChoice)
++++++++Computer+=+ComputerList[ComputerChoice_int+-1]
++++except+Exception+as+e:
++++++++if+e.__class__.__name__+==+"ValueError":
++++++++++++print("You+can+not+leave+this+blank+'%25s',+try+again"+%25+(ComputerChoice,))
++++++++++++print("")
++++++++elif+e.__class__.__name__+==+"IndexError":
++++++++++++print("You+can+not+input+numbers+bigger+than+{},+try+again".format(len(ComputerList)))
++++++++++++print("")
++++else:
++++++++break|code-block|syntax|javascript|1579217|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

What is happening is that you are catching just ValueError like strings or empty values. The number 4 is not an error because 4 is an integer. If you want to handle with ValueError and IndexError you need to do it:

<pre><code>#Create a list for when they select the computer they want
ComputerList = ["(1)Home Basic $900", "(2)Office $1200", "(3)Gamer $1500", "(4)Studio $2200"]
#Ask them what they want and repeat if left blank
while True:
 ComputerChoice = input("What computer would you like to buy?(Use the number beside it 1-4): ")
 print("")
 try:
 ComputerChoice_int = int(ComputerChoice)
 Computer = ComputerList[ComputerChoice_int -1]
 except Exception as e:
 if e.__class__.__name__ == "ValueError":
 print("You can not leave this blank '%s', try again" % (ComputerChoice,))
 print("")
 elif e.__class__.__name__ == "IndexError":
 print("You can not input numbers bigger than {}, try again".format(len(ComputerList)))
 print("")
 else:
 break
</code></pre>

I have been trying to get my code to repeat for a list it works if it is left blank but if the input is above 4 in breaks, I'm still trying to get the hang of python

I've tried finding a solutions for this but can't figure out what needs to be where it should go

<pre><code>#Create a list for when they select the computer they want
ComputerList = ["(1)Home Basic $900", "(2)Office $1200", "(3)Gamer $1500", "(4)Studio $2200"]
#Ask them what they want and repeat if left blank
while True:
 ComputerChoice = input("What computer would you like to buy?(Use the number beside it 1-4): ")
 print("")
 try:
 ComputerChoice_int = int(ComputerChoice)
 except ValueError:
 print("You can not leave this blank '%s', try again" % (ComputerChoice,))
 print("")
 else:
 break
</code></pre>

I expected it to repeat but it comes up with 

<pre><code>Traceback (most recent call last):
 File "\\hnhs-fs01\StudentUsers$\17031\Documents\11 DTG\1.7\Assement\Assessment computer.py", line 69, in &lt;module&gt;
 Computer = ComputerList[ComputerChoice_int -1]
IndexError: list index out of range
</code></pre>

How to repeat an input for an input

我一直在尝试让我的代码对列表进行重复，如果将其留空则可以工作，但如果输入在中断中大于4，我仍在尝试掌握python的诀窍我试着为这个问题找到一个解决方案，但不知道该怎么做#Create a list for when they select the computer they wantComputerList = ["...

问如何为输入重复输入
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