Solving the problem of PHP regular code validation string

Find the PHP regular code validation string for the segment
String rules: Can be combined with pure or pure letters, can only use "-" can not use Chinese characters, other character symbols and the beginning of the string cannot be "-", the end can not be "-"

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PHP Code

Preg_match ('/^[a-z0-9]+[a-z0-9-]*[a-z0-9]+$/i ', $string);
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I'm just picking the wrong

1 floor match not one character:)
2 floor is also, \w also contains _, landlord do not
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The 1 floor of the regular is slightly modified to fit the case of a character:

  
  
  

   
   
   PHP Code
   
   
   
/^[a-z0-9]+[a-z0-9-]*[a-z0-9]+| [a-z0-9]+$/i
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$str = ' \w+[0-9a-za-z\-]+\w$ '
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I'm here to make a fuss.

    
    
    

     
     
     PHP Code
     
     
     
/^[0-9a-z][-0-9a-z]*[0-9a-z]$/i
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