php笔记：spl iterators

appenditerator:

$a=new ArrayIterator(array('a','b','c'));$b=new ArrayIterator(array('j','k','l'));$appendIte=new AppendIterator();$appendIte->append($a);$appendIte->append($b);foreach ($appendIte as $value) {    echo $value.", ";}

输出：a, b, c, j, k, l,

ArrayIterator:

ArrayIterator::asort: sort array by values

$a=new ArrayIterator(array(4,3,6,4,2));$a->asort();foreach ($a as $value) {    echo $value.', '; }

DirectoryIterator: a simple interface for viewing the contents of filesystem directories.

for example:

deleting all files in a directory except the one which is last modified

$directory=dirname(__FILE__)."/demo";$filenames=array();$iterator=new DirectoryIterator($directory);foreach($iterator as $fileinfo){     if($fileinfo->isFile()     {           $filenames[fileinfo->getMTime()]=$fileinfo->getFilename();       }}ksort($filenames);print_r($filenames);$i=0;if(sizeof($filenames)>1){    if($i>0)    {       echo $file."\n";       unlink($directory."/".$file);     }     $i++;}}

FileSystemIterator

$it=new FilesystemIterator(dirname(__FILE__));foreach ($it as $fileinfo){    echo $fileinfo->getFilename().",  ";}