php - PHP preg_match 查找多次出现

Question

正则表达式在 PHP 中使用 preg_match 查找多次出现的相同字符串的正确语法是什么？

例如，查找以下字符串是否在以下段落中出现两次：

$string = "/brown fox jumped [0-9]/";

$paragraph = "The brown fox jumped 1 time over the fence. The green fox did not. Then the brown fox jumped 2 times over the fence"

if (preg_match($string, $paragraph)) {
echo "match found";
}else {
echo "match NOT found";
}

Answer 1

你想用preg_match_all(). 这是它在您的代码中的外观。实际函数返回找到的项目数，但$matches数组将保存结果：

<?php
$string = "/brown fox jumped [0-9]/";

$paragraph = "The brown fox jumped 1 time over the fence. The green fox did not. Then the brown fox jumped 2 times over the fence";

if (preg_match_all($string, $paragraph, $matches)) {
  echo count($matches[0]) . " matches found";
}else {
  echo "match NOT found";
}
?>

将输出：

找到 2 个匹配项