PHP 函数使用案例的深入剖析

$arr1 = ['foo', 'bar'];$arr2 = ['baz', 'qux'];$merged = array_merge($arr1, $arr2); // 结果：['foo', 'bar', 'baz', 'qux']

$arr = ['foo', '', 'bar', '0', 'qux'];$filtered = array_filter($arr, 'strlen'); // 结果：['foo', 'bar', 'qux']

$str = 'Hello world!';$length = strlen($str); // 结果：13

$str = 'ABCDEF';$sub = substr($str, 2, 3); // 结果：'CDE'

$num = 3.14159;$rounded = round($num, 2); // 结果：3.14

$num = -123;$absolute = abs($num); // 结果：123

$filename = 'myfile.txt';$content = file_get_contents($filename); // 读取文件内容

$filename = 'myfile.txt';$content = 'This is a new line.';file_put_contents($filename, $content); // 写入新行

<?php // 假设 $data 是一个包含表格数据的关联数组$html = '<table border="1">';$html .= '<thead>';$html .= '<tr>';foreach ($data[0] as $key =&gt; $value) {    $html .= "<th>$key</th>";}$html .= '</tr>';$html .= '</thead>';$html .= '<tbody>';foreach ($data as $row) {    $html .= '<tr>';    foreach ($row as $value) {        $html .= "<td>$value</td>";    }    $html .= '</tr>';}$html .= '</tbody>';$html .= '';echo $html;?&gt;