php怎么实现字符串截取

<code class="php">$string = 'Hello World';

// 截取前 5 个字符
$substring1 = substr($string, 0, 5); // 输出: Hello

// 截取第 6 个字符到字符串末尾
$substring2 = substr($string, 5); // 输出: World</code>

<code class="php">$string = '日本語テスト';

// 截取前 3 个字符
$substring1 = mb_substr($string, 0, 3); // 输出: 日本語

// 截取第 4 个字符到字符串末尾
$substring2 = mb_substr($string, 3); // 输出: テスト</code>

<code class="php">$string = 'The quick brown fox jumped over the lazy dog';

// 截取 "quick" 一词
$substring1 = preg_match('/quick/', $string, $matches) ? $matches[0] : '';

// 截取 "fox" 和 "dog" 之间的所有字符
$substring2 = preg_match('/fox.*dog/', $string, $matches) ? $matches[0] : '';</code>

<code class="php">$string = 'The quick brown fox jumped over the lazy dog';

// 截取 "quick" 一词
$arr = explode(' ', $string);
$substring1 = $arr[0];

// 截取 "fox" 和 "dog" 之间的所有字符
$arr = explode(' fox ', $string);
$substring2 = $arr[1];</code>