php基本函数汇总

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']);    }  }}

4.数组排序 a - b 是数字数组写法 遇到字符串的时候就要

var test = ['ab', 'ac', 'bd', 'bc'];test.sort(function(a, b) {  if(a < b) {    return -1;  }  if(a > b) {    return 1;  }  return 0;});

5.array_reduce

$raw = [1,2,3,4,5,];// array_reduce 的第三个参数是 $result 的初始值array_reduce($raw, function($result, $value) {  $result[$value] = $value;  return $result;}, []);// [1 => 1, 2 => 2, ... 5 => 5]

6.array_map 闭包中只接受一个或者多个参数，闭包的参数数量和 array_map 本身的参数数量必须一致

$input = ['key' => 'value'];array_map(function($key, $value) {  echo $key . $value;}, array_keys($input), $input)// 'keyvalue'$double = function($item) { return 2 * $item;}$result = array_map($double, [1,2,3]);// 2 4 6

7.繁殖兔子

$month = 12;  $fab = array();  $fab[0] = 1;  $fab[1] = 1;   for ($i = 2; $i < $month; $i++)   {     $fab[$i] = $fab[$i - 1] + $fab[$i - 2];   }   for ($i = 0; $i < $month; $i++)   {     echo sprintf("第{%d}个月兔子为：{%d}",$i, $fab[$i])."<br/>";   }