php从文件夹随机读取文件的方法
本文实例讲述了php从文件夹随机读取文件的方法。分享给大家供大家参考。具体实现方法如下：
function RandomFile($folder='', $extensions='.*'){
// fix path:
$folder = trim($folder);
$folder = ($folder == '') ? './' : $folder;
// check folder:
if (!is_dir($folder)){ die('invalid folder given!'); }
// create files array
$files = array();
// open directory
if ($dir = @opendir($folder)){
// go trough all files:
while($file = readdir($dir)){
if (!preg_match('/^\.+$/', $file) and
preg_match('/\.('.$extensions.')$/', $file)){
// feed the array:
$files[] = $file;
}
}
// close directory
closedir($dir);
}
else {
die('Could not open the folder "'.$folder.'"');
}
if (count($files) == 0){
die('No files where found :-(');
}
// seed random function:
mt_srand((double)microtime()*1000000);
// get an random index:
$rand = mt_rand(0, count($files)-1);
// check again:
if (!isset($files[$rand])){
die('Array index was not found! very strange!');
}
// return the random file:
return $folder . $files[$rand];
}
//用法演示：
// "jpg|png|gif" matches all files with these extensions
print RandomFile('test_images/','jpg|png|gif');
// returns test_07.gif
// ".*" matches all extensions (all files)
print RandomFile('test_files/','.*');
// returns foobar_1.zip
// "[0-9]+" matches all extensions that just
// contain numbers (like backup.1, backup.2)
print RandomFile('test_files/','[0-9]+');
// returns backup.7
希望本文所述对大家的php程序设计有所帮助。
