删除字符串的preg_replace重复字符

Question

$value = "ABCC@CmCCCCm@CCmC@CDEF";

$clear = preg_replace('/@{1,}/', "", $value);

我需要删除重复的@和得到的东西，如：

ABCC@CmCCCCmCCmCCDEF（我只需要先@）

怎么办那？

Answer 1

一个正则表达式的方法：

$clear = preg_replace('~(?>@|\G(?<!^)[^@]*)\K@*~', '', $value); 

细节：

(?:   # open a non capturing group 
    @   # literal @ 
    |   # OR 
    \G(?<!^) # contiguous to a precedent match, not at the start of the string 
    [^@]*  # all characters except @, zero or more times 
)\K   # close the group and reset the match from the result 
@*   # zero or more literal @ 

Answer 2

这给一试：

// The original string 
$str = 'ABCC@CmCCCCm@CCmC@CDEF'; 
// Position of the first @ sign 
$pos = strpos($str, '@'); 
// Left side of the first found @ sign 
$str_sub_1 = substr($str, 0, $pos + 1); 
// Right side of the first found @ sign 
$str_sub_2 = substr($str, $pos); 
// Replace all @ signs in the right side 
$str_sub_2_repl = str_replace('@', '', $str_sub_2); 
// Join the left and right sides again 
$str_new = $str_sub_1 . $str_sub_2_repl; 
echo $str_new;