如何在Controller中截断$row数组的member与email拼接内容？

在Controller中编写了如下代码用于给DataTable提供数据，拼接$row['member']和$row['email']后希望截断过长的内容，但尝试模板引擎的|truncate(5)、[email|truncate(5)]语法均无效：

$values = array(
    $row['member'] . '-' . $row['email'],
    $row['transactionDate'],
    $row['currency'],
    $row['amount'],
    empty($row['amountReceived']) ? '0.00' : $row['amountReceived'],
    $row['status'],
    $row['status'] == 'Pending' ? $action : ''
);

你是在PHP控制器代码中处理数据，模板引擎的truncate过滤器语法在这里不生效，需要用PHP原生的字符串截断方法：

方法1：单字节字符截断（用substr） #

直接对拼接后的字符串截断，超过指定长度追加省略号：

$combined = $row['member'] . '-' . $row['email'];
$truncated = strlen($combined) > 5 ? substr($combined, 0, 5) . '...' : $combined;

$values = array(
    $truncated,
    $row['transactionDate'],
    $row['currency'],
    $row['amount'],
    empty($row['amountReceived']) ? '0.00' : $row['amountReceived'],
    $row['status'],
    $row['status'] == 'Pending' ? $action : ''
);

方法2：多字节字符截断（用mb_substr，支持中文） #

如果内容包含中文等多字节字符，用mb_substr避免乱码：

$combined = $row['member'] . '-' . $row['email'];
$maxLength = 5;
$truncated = mb_strlen($combined) > $maxLength ? mb_substr($combined, 0, $maxLength) . '...' : $combined;

$values = array(
    $truncated,
    $row['transactionDate'],
    $row['currency'],
    $row['amount'],
    empty($row['amountReceived']) ? '0.00' : $row['amountReceived'],
    $row['status'],
    $row['status'] == 'Pending' ? $action : ''
);

方法3：按单词截断（避免截断到单词中间） #

如果需要保持单词完整性，可自定义函数：

function truncateByWord($str, $maxLength = 5, $suffix = '...') {
    if (mb_strlen($str) <= $maxLength) {
        return $str;
    }
    $truncated = mb_substr($str, 0, $maxLength);
    $lastSpace = mb_strrpos($truncated, ' ');
    if ($lastSpace !== false) {
        $truncated = mb_substr($truncated, 0, $lastSpace);
    }
    return $truncated . $suffix;
}

$combined = $row['member'] . '-' . $row['email'];
$truncated = truncateByWord($combined, 5);

$values = array(
    $truncated,
    $row['transactionDate'],
    $row['currency'],
    $row['amount'],
    empty($row['amountReceived']) ? '0.00' : $row['amountReceived'],
    $row['status'],
    $row['status'] == 'Pending' ? $action : ''
);

内容的提问来源于stack exchange，提问作者jim