Home > Article > Backend Development > A simple example of PHP judging whether the brackets in the expression match
The following editor will bring you a simple example of PHP judging whether the brackets in the expression match. The editor thinks it’s pretty good, so I’ll share it with you now and give it as a reference. Let’s follow the editor and take a look.
is as follows:
##
<?php /** * title: 判断表达式中括号是否匹配 * Description: () 匹配 )(不匹配 利用压栈和出栈 * @author Mr Lv */ function isValid($expstr) { $temp = array(); for ($i=0; $i<strlen($expstr); $i++) { $ch = $expstr[$i]; switch($ch) { case '(': array_push($temp, '('); break; case ')': if (empty($temp) || array_pop($temp) != '(') { return "缺少左括号("; } } } return empty($temp) == true ? "表达式匹配" : "缺少右括号)"; } $expstrA = "(1+3(6*4)-(2+3))()("; $expstrB = "(1+3(6*4)-(2+3))()"; $expstrC = "(1+3(6*4)-(2+3)))"; echo isValid($expstrA); echo "<br>"; echo isValid($expstrB); echo "<br>"; echo isValid($expstrC); ?>Page information:
缺少右括号) 表达式匹配 缺少左括号(
The above is the detailed content of A simple example of PHP judging whether the brackets in the expression match. For more information, please follow other related articles on the PHP Chinese website!