PHP关于SPL学习经历

<?php
namespace App\Http\Controllers;

class WelcomeController extends Controller
{
    use \App\Traiter\TraitTest;// 使用traitpublic function show()
    {
        $iterator = new \NoRewindIterator($this->yieldTest());//生成一个Iterator
        foreach ($iterator as $key => $value) {
            var_dump($value);
        }
        $this->myTest();
        $fileIterator = new \NoRewindIterator($this->splFileObject());
        foreach ($fileIterator as $key => $value) {
            var_dump($value);
        }
         $path = "../";
        $this->splFileObjec($path);//
        $this->recDirectoryIterator($path);
        $recArrayIterator = $this->recArrIterator();    
        $this->recIterIterator($recArrayIterator);    
        $this->recTreeIterator($recArrayIterator);
    }

    public function yieldTest()
    {
        $array = [
            'a',
            'b',
            'c',
            'd',
            'e'
        ];
        $iterator = new \ArrayIterator($array);
        foreach ($iterator as $key => $value) {
            yield $value;
        }
    }

    public function splFileObject()
    {
        $flieObject = new \SplFileObject(__FILE__, 'r');
        while (!$flieObject->eof()) {
            yield $flieObject->fgets();
        }
    }

    public function dirIterator($path)
    {
        $dirIterator = new \DirectoryIterator($path);
        foreach ($dirIterator as $fileInfo) {
            if ($fileInfo->isDir()) {
                var_dump($fileInfo->getFilename());
            }
        }
    }

    public function recDirectoryIterator($path)
    {
        $recDirectoryIterator = new \RecursiveDirectoryIterator($path);
        $recIteratorIterator = new \RecursiveIteratorIterator($recDirectoryIterator, \RecursiveIteratorIterator::SELF_FIRST);
        foreach ($recIteratorIterator as $name => $object) {
            // if ($object->isDir()) {
            //     var_dump($object->getPath());
            // }

            if (in_array($object->getFileName(), [".", ".."])) {
                continue;
            }
            
            var_dump($name);
        }
    }

    public function recArrIterator()
    {
        $fruits = array("a" => "lemon" , "b" => ["orange", "taozi"], "c" => array("d" => "apple", "p" => "pear", "sub" => ["ch1", "ch2", "ch3"]));
        var_dump($fruits); 
        $iterator = new \RecursiveArrayIterator($fruits);
        while ($iterator->valid()) {
            if ($iterator->hasChildren()) {
                foreach ($iterator->getChildren() as $key => $value) {
                    var_dump($value);
                }
            } else {　　　　　　　　　　var_dump($value);　　　　　　　　}

$iterator->next();
        }
        return $iterator;
    }

    public function recIterIterator(\RecursiveArrayIterator $recArrayIterator)
    {
        $iterator = new \RecursiveIteratorIterator($recArrayIterator);
        foreach ($iterator as $key => $value) {
            $depth = $iterator->getDepth();
            var_dump("depth: $depth, key: $key, value: $value");
        }
    }

    public function recTreeIterator(\RecursiveArrayIterator $recArrayIterator)
    {
        $iterator = new \RecursiveTreeIterator($recArrayIterator, null, null, \RecursiveIteratorIterator::LEAVES_ONLY);
        foreach ($iterator as $key => $value) {
            var_dump($value);
        }
    }

}



?>

这里有几个点说明一下

　　一、yield关键字

　　　　1、yield是可以让一个函数重复返回。把函数加载到迭代器Iterator里，然后foreach逐个读取返回值。

　　　　2、游历大文件时，通常的办法是一次性加载到数组里，这样的话有可能php内存溢出。用yield结合SplFileObject()类解决这个问题，原理是通过该类的fgets()每读一行就处理一行。工作中经常遇到批量导入数据到数据，该方法可以使用

 　　二、RecursiveArrayIterator()类

　　　　1、通常我们处理一个多维数组，想要获取最底层的数组比较困难，需要反复判断Is_array()，然后再次循环，而且不知道会有多少层，这是蛋都隐隐作痛了。比如一家公司下有多个部门，每个部门构成的元素有人和部门，一层层下去，我们需要查找每个部门的人时，就很头大了。通过RecursiveArrayIterator($array)就可以轻松解决了。

 

来源：https://www.cnblogs.com/longerQiu/p/11372116.html