在字符串中查找有效的十六进制 - PHP: Find valid hex in string

PHP: Find valid hex in string

假设我有一个字符串:$str=abcef7ha43HEX_STRING7sf6gHEX_STRING //"HEX_STRING "is any valid hex string .

我需要在$str中找到HEX_STRING并将其替换为pack("H*",HEX_STRING)的结果。我该怎么做呢?

你应该这样做:

$string = 'abcef7ha43{20}7sf6g';
$new_string = preg_replace_callback('/'{((?:[a-f0-9]{2})+)'}/i', function($m){
    return pack("H*",$m[1]);
}, $string); // anonymous function requires PHP 5.3+
echo $new_string;

在线regex演示|在线php演示

解释:

'{ # Start with {
    ( # Group '1
        (?: # Ignore this group
            [a-f0-9]{2} # abcdef0123456789 two times = HEX
        )+ # Repeat 1 or more times
    )
'} #End with }
#and the i modifier for case insensitive matching

编辑: OP不想/有花括号{}，所以这里有一个解决方案，检测每个十六进制字符并转换它:

$string = 'abcef7ha43207sf6g';
$new_string = preg_replace_callback('/[a-f0-9]{2}/i', function($m){
    return pack("H*",$m[0]);
}, $string);
echo $new_string;