Python字符串檢查

Question

有人可以告訴我如何檢查用戶的輸入是否包含數字，並且只包含數字和字母？

這裏是我到目前爲止有：

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

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

我想打印的最後一條語句全部檢查完成之後。我似乎無法弄清楚如何檢查字符串。

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()測試字符串是否都是字母數字。如果你需要至少一個數字，然後逐個用.isdigit()測試數字，並尋找使用any()至少一個可以發現：

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.") 

參考文獻：anyalnumisdigit