如何确定是否提供了一串文本？

Question

例子：

`Hello @john` -> true 
`Hello @john ` -> false 
`Hello @john.` -> false 
`Hello @john i` -> false 

Answer 1

尝试正则表达式：@\p{L}+(?:$|\n)

\p{L} -> Match matches any kind of letter from any language 
$  -> Match End of the string 

现场演示：https://regex101.com/r/m9du5M/2

Answer 2

如果您想验证用模式的用户提字符串，您在说明显示它是最好写入String的扩展名。这将验证数据。

尝试：

extension String { 
    func mention() -> Bool { 
     let pattern = "@[a-zA-Z]+$" 
     guard let _ = self.range(of:pattern, options: .regularExpression) else { 
      return false 
     } 
     return true 
    } 
} 

测试用例：

let input = ["Hello @john", "Hello @john ", "Hello @john.", "Hello @john i,", "@_____", "@Вася\n"] 

for item in input { 
    if !item.mention() { 
     print("Failed to get mention at | \(item) |") 
    } 
} 

验证：

Failed to get mention at | Hello @john | 
Failed to get mention at | Hello @john. | 
Failed to get mention at | Hello @john i, | 
Failed to get mention at | @_____ | 
Failed to get mention at | @Вася 
|