正则表达式 - 获取匹配

(?:pattern) 非获取匹配, 
    eg: (?:bbb)(ccc)匹配aaabbbcccddd, 匹配上bbbccc,但\1位ccc
        (bbb)(?:ccc)匹配aaabbbcccddd, 匹配上bbbccc,但\1位bbb

(?=pattern) 正向肯定预查,非获取匹配
    eg: (bbb)(?=ccc)匹配aaabbbcccddd 匹配上bbb
(?!pattern) 正向否定预查,非获取匹配
    eg: (bbb)(?!aaa)匹配aaabbbcccddd 匹配上bbb
    
(?<=pattern) 反向肯定预查,非获取匹配
    eg: (?<=bbb)(ccc)匹配aaabbbcccddd 匹配上ccc
(?!pattern) 反向否定预查,非获取匹配
    eg: (?<!aaa)(ccc)匹配aaabbbcccddd 匹配上ccc