php数组的逐行写入文件与读取

<?php

/**
 *
 * 对数组$arr1=['Apple Orange Banana Strawberry'] 写入文件，并读取
 **/
class IoFile
{
    private $path;

    public function __construct($paths)
    {
        $this->path = $paths;
    }

//写入
    public function inter($arr)
    {
        if (!is_array($arr) && !empty($arr)) {
            return '数组异常';
        }

        $file = fopen($this->path, 'w');
        if (!$file) {
            return '文件打开失败';
        }
        foreach ($arr as $k => $v) {
            fwrite($file, $v);
            if ($v != end($arr)) {
                fwrite($file, "
");
            }
        }
        fclose($file);
    }

//读取
    public function outer()
    {
        $arr = [];
        if (!file_exists($this->path)) {
            return "文件不存在！";
        }
        $file = fopen($this->path, 'r');
        if (!$file) {
            return '文件打开失败';
        }
        while (!feof($file)) {
            $arr[] = str_replace("
", '', fgets($file));
        }
        fclose($file);
        return $arr;
    }
}

$arr1 = ['Apple', 'Orange', 'Banana', 'Strawberry'];
$path = 'tt.txt';
$obj = new IoFile($path);
echo $obj->inter($arr1);

echo '<hr/>';
var_dump($obj->outer());