Regular anonymous capture named captures

know the power of regular expressions recently learned some, encounter problems, nonsense not much to say on the code:

$str = 'Mr.Ck-@139.com';if(preg_match('(?:<#user>[a-zA-Z0-9_-.]+)@(?:<#host>[a-zA-Z0-9_-.]+)', $str, $match)) {    print_r($match);}$str = '123,456,78,90';if(preg_match('(?[0-9]+)(.(?[0-9]+))*', $str, $match)) {    print_r($match);}

error message :

Warning:preg_match (): Unknown modifier ' @ D:\webServ\index.php on line 15

Warning:preg_match (): Unknown modifier ' (' in D:\webServ\index.php to line 23

I do not know whether it is because of the PHP function problem, I believe this expression should be no problem, just preg_match the function of what mechanism caused the put?

Reply content:

Know the power of regular expressions recently learned some, encounter problems, nonsense not much to say on the code:

$str = 'Mr.Ck-@139.com';if(preg_match('(?:<#user>[a-zA-Z0-9_-.]+)@(?:<#host>[a-zA-Z0-9_-.]+)', $str, $match)) {    print_r($match);}$str = '123,456,78,90';if(preg_match('(?[0-9]+)(.(?[0-9]+))*', $str, $match)) {    print_r($match);}

error message :

Warning:preg_match (): Unknown modifier ' @ D:\webServ\index.php on line 15

Warning:preg_match (): Unknown modifier ' (' in D:\webServ\index.php to line 23

I do not know whether it is because of the PHP function problem, I believe this expression should be no problem, just preg_match the function of what mechanism caused the put?

• preg_matchThe first parameter is a regular string, and the regular requires the start and end tags you don't have here.

'(?:<#user>[a-zA-Z0-9_-.]+)@(?:<#host>[a-zA-Z0-9_-.]+)'(?[0-9]+)(.(?[0-9]+))*

Switch

'/(?:<#user>[a-zA-Z0-9_-.]+)@(?:<#host>[a-zA-Z0-9_-.]+)/''/(?[0-9]+)(.(?[0-9]+))*/'

• After the above changes are still wrong, the reason for the error is:
  
  
  • _-.The lines within the brackets - have special meanings (refer a-z to, 0-9 ).
  • The second regular in (? this notation is incorrect, PHP error message is:
    Warning: preg_match(): Compilation failed: unrecognized character after (? or (?- at offset 2 in T:\1.php on line xxBecause do not know your second specific to do what, you can directly delete the ? number, or the number after the number to ? : solve the problem of error.

The code after the change:

php
  
   [a-zA-Z0-9_\-.]+)@(?:<#host>[a-zA-Z0-9_\-.]+)/', $str, $match)) {    print_r($match);}$str = '123,456,78,90';if(preg_match('/([0-9]+)(.([0-9]+))*/', $str, $match)) {    print_r($match);}

I solved the number, the final question.

