Python 检查字符串中的任何字符是否为字母数字
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Checking if any character in a string is alphanumeric
提问by rachitmishra25
I want to check if any character in a string is alphanumeric. I wrote the following code for that and it's working fine:
我想检查字符串中是否有任何字符是字母数字。我为此编写了以下代码并且它工作正常：
s = input()
temp = any(i.isalnum() for i in s)
print(temp)
The question I have is the below code, how is it different from the above code:
我的问题是下面的代码，它与上面的代码有什么不同：
for i in s:
if any(i.isalnum()):
print(True)
The for-loop iteration is still happening in the first code so why isn't it throwing an error? The second code throws:
for 循环迭代仍在第一个代码中发生，为什么它不抛出错误？第二个代码抛出：
Traceback (most recent call last): File "", line 18, in TypeError: 'bool' object is not iterable
回溯（最近一次调用）：文件“”，第 18 行，在 TypeError 中：“bool”对象不可迭代
采纳答案by JohanL
In your second function you apply anyto a single element and not to the whole list. Thus, you get a single bool element if character iis alphanumeric.
在您的第二个函数中，您应用于any单个元素而不是整个列表。因此，如果字符i是字母数字，您将得到一个 bool 元素。
In the second case you cannot really use anyas you work with single elements. Instead you could write:
在第二种情况下，any当您使用单个元素时，您无法真正使用。相反，你可以写：
for i in s:
if i.isalnum():
print(True)
break
Which will be more similar to your first case.
这将更类似于您的第一个案例。
回答by Stephen Rauch
any()expects an iterable. This would be sufficient:
any()期待一个迭代。这就足够了：
isalnum = False
for i in s:
if i.isalnum():
isalnum = True
break
print(isalnum)
