php将数组或字符串写入文件

//将数组保存在文件里
function export_to_file($file, $variable) {
    $fopen = fopen($file, 'wb');
    if (!$fopen) {
        return false;
    }
    fwrite($fopen, "<?
php
return ".var_export($variable, true).";
?
>");
    fclose($fopen);
    return true;
}
//将字符串写入文件
function put_to_file($file, $content) {
    $fopen = fopen($file, 'wb');
    if (!$fopen) {
        return false;
    }
    fwrite($fopen, $content);
    fclose($fopen);
    return true;
}