正则表达式regex

概述

deprecated

已弃用 : 使用pkg: regex_pcre2替代

主要提供正则匹配/搜索/替换功能，接口和C++11标准库中保持一致。

功能使用说明

正则匹配

匹配字符串域传入的正则表达式，如果匹配则返回true，否则返回false(参照std::regex_match )

bool regex.match(string str, string rgx, RegexFlags flag = 0)

正则搜索

将所有匹配到的结果以字符串列表的形式返回(参照std::regex_search )

array regex.search(string str, string rgx, RegexFlags flag = 0)

• 当匹配到空的时候，固定向前移一个字符，否则会导致死循环。 比如：regex.search("abc", "[a]*")的匹配过程：

"abc" -> 匹配到"a"
"bc"  -> 匹配到"",前移一个字符
"c"   -> 匹配到"",前移一个字符
""    -> 匹配到"",匹配结束

正则替换(参照[std::regex_replace]

将满足匹配的部分按照指定格式进行替换(https://zh.cppreference.com/w/cpp/regex/regex_replace) )

string regex.replace(string str, string rgx, string fmt, RegexFlags flag)

举个例子：

// Match
bool is_match = false;
is_match = regex.match("subject", "(sub)(.*)", RegexFlags.DEFAULT); // is_match = true
is_match = regex.match("subject", "(sub)....");                     // is_match = true
is_match = regex.match("subject", "sub..");                         // is_match = flase

// Search
array search_ret = regex.search("this subject has a submarine as a subsequence", "\\b(sub)([^ ]*)");
//search_ret = [
//                [ "subject", "sub", "ject", ],
//                [ "submarine", "sub", "marine", ],
//                [ "subsequence", "sub", "sequence", ],
//             ];
      
// Replace
string new_str = regex.replace("this is a subsequence in the string", "\\b(sub)([^ ]*)", "sub-$2");
// new_str = "this is a sub-sequence in the string");

RegexFlags说明

gs中的枚举值	c++标准库对应值	说明
RegexFlags.DEFAULT	std::regex_constants::match_default	Default matching behavior. This constant has a value of zero**.
RegexFlags.NOT_BOL	std::regex_constants::match_not_bol	The first character is not considered a beginning of line ("^" does not match).
RegexFlags.NOT_EOL	std::regex_constants::match_not_eol	The last character is not considered an end of line ("$" does not match).
RegexFlags.NOT_BOW	std::regex_constants::match_not_bow	The escape sequence "\b" does not match as a beginning-of-word.
RegexFlags.NOT_EOW	std::regex_constants::match_not_eow	The escape sequence "\b" does not match as an end-of-word.
RegexFlags.ANY	std::regex_constants::match_any	Any match is acceptable if more than one match is possible.
RegexFlags.NOT_NULL	std::regex_constants::match_not_null	Empty sequences do not match.
RegexFlags.CONTINUOUS	std::regex_constants::match_continuous	The expression must match a sub-sequence that begins at the first character. Sub-sequences must begin at the first character to match.
RegexFlags.PREV_AVAIL	std::regex_constants::match_prev_avail	One or more characters exist before the first one. (match_not_bol and match_not_bow are ignored)
RegexFlags.FORMAT_DEFAULT	std::regex_constants::format_default	Uses the standard formatting rules to replace matches (those used by ECMAScript's replace method)." "This constant has a value of zero**.
RegexFlags.FORMAT_SED	std::regex_constants::format_sed	Uses the same rules as the sed utility in POSIX to replace matches.
RegexFlags.FORMAT_NO_COPY	std::regex_constants::format_no_copy	The sections in the target sequence that do not match the regular expression are not copied when replacing matches.
RegexFlags.FORMAT_FIRST_ONLY	std::regex_constants::format_first_only	Only the first occurrence of a regular expression is replaced.