Regular expression system tutorial (IV) _ PHP Tutorial

Regular expression system tutorial (4 ). 4. operators with the same priority perform operations from left to right. operations with different priorities are first high, then low. The priorities of various operators are as follows: 4. operation priority of various operators

Operations with the same priority are performed from left to right. operations with different priorities are first high and then low. The priorities of operators are as follows:

Operator	Description
	Escape character
(),(? :),(? =), []	Parentheses and square brackets
*, + ,?, {N}, {n ,}, {n, m}	Qualifier
^, $, Anymetacharacter	Location and order
|	"Or" operation

Http://www.bkjia.com/PHPjc/532538.htmlwww.bkjia.comtruehttp://www.bkjia.com/PHPjc/532538.htmlTechArticle4. operators of the same priority of the operation from left to right operations, different priorities of the operation first high, then low. The priorities of various operators are as follows: operator description...