Python字符串检查

Question

有人可以告诉我如何检查用户的输入是否包含数字，并且只包含数字和字母？

这里是我到目前为止有：

employNum = input("Please enter your employee ID: ") 

if len(employNum) == 8: 
    print("This is a valid employee ID.") 

我想打印的最后一条语句全部检查完成之后。我似乎无法弄清楚如何检查字符串。

Answer 1

>>> employNum = input("Please enter your employee ID: ") 
Please enter your employee ID: asdf890 
>>> all(i.isalpha() or i.isdigit() for i in employNum) 
True 
>>> employNum = input("Please enter your employee ID: ") 
Please enter your employee ID: asdfjie-09 
>>> all(i.isalpha() or i.isdigit() for i in employNum) 
False 


>>> def threeNums(s): 
... return sum(1 for char in s if char.isdigit())==3 
... 
>>> def atLeastThreeNums(s): 
... return sum(1 for char in s if char.isdigit())>=3 
... 
>>> def threeChars(s): 
... return sum(1 for char in s if char.isalpha())==3 
... 
>>> def atLeastThreeChars(s): 
... return sum(1 for char in s if char.isalpha())>=3 
... 
>>> rules = [threeNums, threeChars] 
>>> employNum = input("Please enter your employee ID: ") 
Please enter your employee ID: asdf02 
>>> all(rule(employNum) for rule in rules) 
False 
>>> employNum = input("Please enter your employee ID: ") 
Please enter your employee ID: asdf012 
>>> all(rule(employNum) for rule in rules) 
False 
>>> employNum = input("Please enter your employee ID: ") 
Please enter your employee ID: asd123 
>>> all(rule(employNum) for rule in rules) 
True 

Answer 2

.alnum()测试字符串是否都是字母数字。如果你需要至少一个数字，然后逐个用.isdigit()测试数字，并寻找使用any()至少一个可以发现：

employNum = input("Please enter your employee ID: ") 

if len(employNum) == 8 and employNum.isalnum() and any(n.isdigit() for n in employNum): 
    print("This is a valid employee ID.") 

参考文献：anyalnumisdigit