php常考功能函数

1.统计数组元素个数

$arr = array(
   '1011,1003,1008,1001,1000,1004,1012',
   '1009',
   '1011,1003,1111'
  );
$result = array();
foreach ($arr as $str) {
 $str_arr = explode(',', $str);
 foreach ($str_arr as $v) {
  // $result[$v] = isset($result[$v]) ? $result[$v] : 0;
  // $result[$v] = $result[$v] + 1;
  $result[$v] = isset($result[$v]) ? $result[$v]+1 : 1;
 }
}
print_r($result);
//Array
(
[1011] => 2
[1003] => 2
[1008] => 1
[1001] => 1
[1000] => 1
[1004] => 1
[1012] => 1
[1009] => 1
[1111] => 1
)

2. 循环删除目录

function cleanup_directory($dir) {
 foreach (new DirectoryIterator($dir) as $file) {
  if ($file->isDir()) {
   if (! $file->isDot()) {
    cleanup_directory($file->getPathname());
   }
  } else {
    unlink($file->getPathname());
  }
 }
  rmdir($dir);
}

3.无限极分类生成树

function generateTree($items){
  $tree = array();
  foreach($items as $item){
    if(isset($items[$item['pid']])){
      $items[$item['pid']]['son'][] = &$items[$item['id']];
    }else{
      $tree[] = &$items[$item['id']];
    }
  }
  return $tree;
}
function generateTree2($items){
  foreach($items as $item)
    $items[$item['pid']]['son'][$item['id']] = &$items[$item['id']];
  return isset($items[0]['son']) ? $items[0]['son'] : array();
}
 
$items = array(
  1 => array('id' => 1, 'pid' => 0, 'name' => '安徽省'),
  2 => array('id' => 2, 'pid' => 0, 'name' => '浙江省'),
  3 => array('id' => 3, 'pid' => 1, 'name' => '合肥市'),
  4 => array('id' => 4, 'pid' => 3, 'name' => '长丰县'),
  5 => array('id' => 5, 'pid' => 1, 'name' => '安庆市'),
);
print_r(generateTree($items));
/**
 * 如何取数据格式化的树形数据
 */
$tree = generateTree($items);
function getTreeData($tree){
  foreach($tree as $t){
    echo $t['name'].'<br>';
    if(isset($t['son'])){
      getTreeData($t['son']);
    }
  }
}

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