Question

我试图用用户输入创建一个列表，该列表中至少包含八个项目。我可以列出该列表并放入用户输入中，但是我需要确认确实有八个项目，如果没有则要求更多。然后我需要打印列表。

我尝试对len（list）<8使用while语句，对于相同的if / else语句。两者都要求额外的输入，但是都没有在最后打印列表。我尝试了一个使用len（list）<8的嵌套循环，而里面是一个if / else循环，但是返回的错误与原始的while语句相同。

>>>def main():
...     userinput= input("Enter a list of at least eight words separated by a comma: ")
...     list= userinput.split(",")
...     while len(list)<7:
...             print("Please enter more words")
...             more_input= input()
...             more_input.split(",")
...             list.append(more_input)
...     print(list)

OR

>>> def main():
...     userinput= input("Enter a list of at least eight words separated by a comma: ")
...     list= userinput.split(",")
...     if len(list)<7:
...             print("Please enter more words")
...             more_input= input()
...             more_input.split(",")
...             list.append(more_input)
...     else:
...             print(list)

while循环出错：即使列表具有最少的必需输入，它也会不断请求更多输入

>>> main()
Enter a list of at least eight words separated by a comma: This, is, a, list
Please enter more words
More, words
Please enter more words
Three, more, words
Please enter more words

if / else循环出错：仅检查一次。如果长度合适，它将打印列表。如果长度不好，则要求更多输入，然后停止。它既不会再次检查长度，也不会打印列表。

Answer 1

如果要将合并的子列表合并到主列表中，请尝试以下操作：

def main():
    list_= []
    print("Enter a list of at least eight words separated by a comma: ")
    while len(list_)<7:
        print("Please enter more words")
        userinput = input()
        temp = userinput.split(",")
        list_ += temp
    print(list_)
main()

输出：

Enter a list of at least eight words separated by a comma: 
Please enter more words
This, is, a, list
Please enter more words
more, words
Please enter more words
three, more, words
['This', ' is', ' a', ' list', 'more', ' words', 'three', ' more', ' words']

注意：避免将变量名称分配为list，因为它是python中的内置关键字。

Answer 2

您的代码似乎还可以，但是问题是您正在拆分来自用户的输入，但是此拆分输入没有变量。我的意思是，您仍在将非拆分输入添加到列表中。我编辑了您可以在下面看到的代码。

def main():
     userinput= input("Enter a list of at least eight words separated by a comma: ")
     input_list = userinput.split(",")
     while len(input_list)<7:
             print("Please enter more words")
             more_input= input()
             splitted_more_input = more_input.split(",") # problem fixed here
             for i in splitted_more_input: # split creates another list 
                 input_list.append(i) # add inputs individual
    print(input_list)

Answer 3

由于您需要重复执行某个函数直到满足特定条件，因此可以按照以下方式使用递归函数

def main():
    userinput= input("Enter a list of at least eight words separated by a comma: ")
    words = userinput.split(",")

    if len(words) == 8:
        print (words)        
    else:
        A = reenter_words(words)
        print (A) 

def reenter_words(words):
    if len(words) == 8:
        return words
    else:
        IN = input("More words are needed:")
        new_words = words + IN.split(",")
        return reenter_words(new_words)

在这里，我递归地调用reenter_words函数，直到从用户那里得到八个单词为止。

样品输出

Enter a list of at least eight words separated by a comma: qq,ww,ee,rr,tt
More words are needed:gg,hh
More words are needed:kk
['qq', 'ww', 'ee', 'rr', 'tt', 'gg', 'hh', 'kk']

希望这会有所帮助！

验证列表的长度，并在必要时添加输入

3 个答案: