\b 单词边界, 单词就是\w组成的
i: With this flag the search is case-insensitive: no difference between A and a (see the example below). g: With this flag the search looks for all matches, without it – only the first match is returned. m: Multiline mode (covered in the chapter Multiline mode of anchors ^ $, flag “m”). s: Enables “dotall” mode, that allows a dot . to match newline character \n (covered in the chapter Character classes). u: Enables full Unicode support. The flag enables correct processing of surrogate pairs. More about that in the chapter Unicode: flag “u” and class \p{…}. y: “Sticky” mode: searching at the exact position in the text (covered in the chapter Sticky flag “y”, searching at position)
Regular Expression
Regular expressions
Regular expression operations
Lesson: Regular Expressions