如何限制输入而不导入重新

发布于 2025-01-14 16:09:52 字数 399 浏览 1 评论 0原文

大家好，尝试询问用户名，但只能使用字母、数字或_。如果提供其他任何信息，我需要再次询问。这是我到目前为止所拥有的，但是当我尝试运行时，它只是继续运行而不是完成。因此，在第一个问题之后，如果我输入像“jack”这样的用户名，它应该只打印用户名：jack，但它只是不断询问代码中的第二个问题“请输入用户名（仅字母和数字）我该如何解决这个问题” ？

Username = input ("What is your username?")

while Username != "^[A-Za-z0-9]*$":
    
    Username = input('Please enter a username(only letters and numbers)')
    
print("Username: ", Username)

原文

hi all trying to ask for username and only letters or numbers or _ can be used. if anything else is provided i need to ask again. this is what i have so far but when i try to run it just keeps going instead of completing.
so after the first question, if i enter username like "jack" it should just print username: jack, but instead it just keeps asking the second question in the code 'Please enter a username(only letters and numbers) how do i fix this?

Username = input ("What is your username?")

while Username != "^[A-Za-z0-9]*quot;:
    
    Username = input('Please enter a username(only letters and numbers)')
    
print("Username: ", Username)

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临走之时 2025-01-21 16:09:52

可以有两种方法。

循环遍历字符串并检查每个字符是否属于字母或数字范围。尽管不建议这样做，因为它消耗时间和内存。
使用str.isalnum()。这很简单，比上一个更好。

代码：

Username = input ("What is your username?")

while not Username.replace('_', '').isalnum(): #Edit: Removed _ as an invalid character
    
    Username = input('Please enter a username(only letters and numbers)')
    
print("Username: ", Username)

There can be two ways.

To cycle through the string and check if each character belongs to the range of letters or numbers. Though this is not advised as it is time and memory consuming.
Using str.isalnum(). This is easy short and better than the previous.

Code:

Username = input ("What is your username?")

while not Username.replace('_', '').isalnum(): #Edit: Removed _ as an invalid character
    
    Username = input('Please enter a username(only letters and numbers)')
    
print("Username: ", Username)

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