📅  最后修改于: 2022-03-11 15:01:33.986000             🧑  作者: Mango
代码示例1
// Add a \s? if a space can be allowed.
// \s stands for white space
// ? says the preceding character may occur once or not occur.
// If more than one spaces are allowed and is optional, use \s*.
// * says preceding character can occur zero or more times.
'##'