$re = '/public ([^ ]++) ([a-z])([^ ]*+) { get; set; }/m';
$str = 'public string symbol { get; set; }
public string pair { get; set; }
public string contractType { get; set; }
public string status { get; set; }
public string baseAsset { get; set; }
public string quoteAsset { get; set; }
public string marginAsset { get; set; }';
$subst = "[JsonPropertyName(\"$2$3\")]\npublic $1 \U$2\E$3 { get; set; }";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php