在 if 语句中匹配两个 preg_matches

Question

我在 if 语句中有 2 个 preg_match，并且 if 其中任何一个都是正确的，我想将它们都打印出来。但是由于某种原因，每次只匹配第一个preg_match，即使它们都具有相同的模式。为什么会这样？

<?php

$string = "how much is it?";
if (preg_match("~\b(how (much|many))\b~", $string, $match1) || preg_match("~\b(how (much|many))\b~", $string, $match2)) {
print_r($match1);
print_r($match2);   
}

?>

结果：

Array ( [0] => how much [1] => how much [2] => much )

预期结果：

Array ( [0] => how much [1] => how much [2] => much )
Array ( [0] => how much [1] => how much [2] => much )

Answer 1

解释：-

由于|| 条件，当第一个是正确的，如果忽略第二个执行。所以第一个输出数组，但第二个给出Notice: Undefined variable: match2 in D:\xampp\htdocs\abc.php on line 6。奇怪的是你没有收到那个错误。

如果您希望两者都作为输出，请使用 && 而不是 ||，以便两者都会检查并打印

所以代码将是：-

<?php

$string = "how much is it?";
if (preg_match("~\b(how (much|many))\b~", $string, $match1) && preg_match("~\b(how (much|many))\b~", $string, $match2)) {
print_r($match1);
print_r($match2);   
}

?>

输出：-https://eval.in/595814

另一种解决方案：-

<?php
    $string = "how much is it?";
    preg_match("~\b(how (much|many))\b~", $string, $match1);
    preg_match("~\b(how (much|many))\b~", $string, $match2);
    print_r($match1);
    print_r($match2);   
?>

更多学习：- http://php.net/manual/en/language.operators.logical.php